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Universiteitsbibliotheek – LibGuides

Search strategy: Where to search

To 'Formulating the search question'

Known item search

Where do you look if you already have information about an article or book, for example the exact title, words from the title or the name of the author(s)? For a known item search applies:

  • Do you know words from the title? Search in WorldCat UU (for the collection of the Utrecht University Library) or Google Scholar with UBUlink. Do you know the exact title? Put the title in double quotes (".."). No hits? Try Google.
  • Do you know only the name of the author(s)? Then Scopus, WoS or WorldCat UU dare the most useful search systems.

Digital journals

Do you know the title of a journal and possibly also the volume? In the overview of digital journals in WorldCat UU you will find current and closed subscriptions of the Utrecht University Library. You can also search by issn or browse the alphabetical list.

e-journal list WCDS

(click on the image to enlarge)

Online access to digital publications

Do you want to read a digital article or an ebook, or do you want to search a specific database?

Utrecht University staff and students can access digital material, for which the library has a license, in different ways.

Read more about these different options on the website of the Utrecht University Library.

Online access via Lean Library

The Lean Library browser extension offers you fast and easy access to a large number of digital scientific sources, no matter where you are. 


In your search for scholarly literature you may sometimes find the UBUlink. This link provides information about the availability of digital publications via the University Library. 

UBU-link button

Where to search? Search engines and databases at Utrecht University Library

Before you can really start looking, you have to think about where to look? Which search engines best suit your topic? What handy, reliable, recommended databases are there?

There are broad, multidisciplinary databases, such as Scopus and Web of Science. There are also databases that are specialized in a specific field, eg Westlaw (law), PsycInfo (psychology) or the MLA (modern languages).

The Utrecht University Library offers an overview and access to various search engines (alphabetical list). There is also an overview of search engines by discipline.

Read the short descriptions and choose the database (or more than one) that best fits your search query.

Most of these search systems are paid for and access is limited to employees and students of Utrecht University. After graduating, you can still search in open access search engines and freely accessible search engines such as PubMed (biomedical literature), Google Scholar or WorldCat.

Where to look for articles?

Articles can be found in almost all academic engines and databases. Filter on document type: articles.
Often used search engines for articles are (amongst others):

NB For articles in print journals you search for the journal title in WorldCat and request the right volume/issue

Articles in scientific journals can be cited. That is, an author uses an article as a source for his or her own work. The articles used are then listed in the bibliography/reference list of the new article.

You can therefore find articles via these reference lists, which we also call snowball searching.
You can also actively search for articles that cite a found source, we call this citation searching.

(see also Search methods)

There are specialised citation databases like Scopus and the Web of Science, but also Google Scholar is a good search engine to search for citations.

Citation searching is also a way to discover journals that publish articles on your subject. For instance go to the Journal Citation Reports.

Look for a well-known journal in your field and click on Cited Journal Data and Citing Journal Data. You will see lists of journals which contain citations to the well-known journal or, on the other hand, are cited by that journal. In this way you will get a network of related journals.

You are often specifically looking for peer-reviewed articles.

Peer review is a way of guaranteeing the scientific nature of an article. In peer review, an article is read and assessed anonymously by peers before publication. You can often find information about  peer review on the magazine's website (in pages like: About this journal' or something similar). See also the Libguide Evaluating sources.

There are several ways to search for peer-reviewed articles:​

  • Some search systems only contain articles from peer-reviewed journals, eg Scopus, Web of Science and many subject-specific databases. For this, read the information from the database itself.
  • Some search engines allow you to filter or limit to peer-reviewed articles. Note: this option is not reliable in all search systems. This option also exists in WorldCat, for example, but not all peer-reviewed articles are equally well described and the filter option is therefore not very useful here.

Newspaper articles can be found in specialised newspaper archives, such as:

  • Delpher for Dutch newspapers up to 1995
  • Nexis Uni for Dutch and foreign newspapers starting from ca. 1995 till now (for help in searching see the library website)
  • Over twenty other archives containing newspapers. Some even have text mining options. See the overview of search systems and filter by type "news and newspapers".

Sort by Type in the list of databases

Where to look for books?

In most scientific search engines and databases you will also find books and (sometimes) chapters from books in addition to articles. You do often have to look for it much more specifically.
In your database, choose to filter by document type, e.g. books and (if possible) also by e-books or print books (or book chapters).

Commonly used search engines for books include:

If you have any questions about e-books? Please visit the e-books webpage at the Utrecht University Library website.

Google Books is the most well known full text database with millions of scanned books. In Google Books you will find both scientific and non-scientific books. Please note that Google Books does not always display the entire text of all books or even the part that you need.

Search Google Books (.nl)
Search Google Books (.com)

Searching Google Books is similar to searching in Google. You will find extensive information on searching and tools on the Help page. Or click on advanced search to find more search options

Search tips:

  • Enter your search terms at With all of the words
  • Change the word order, this gives different results
  • Once you have found a book, try Related books for more results
  • In Google Books you can save 'free books' as PDFs or save your books in My Library (if you have a Google account). Here you can make notes, mark books as have read/to read and make lists you can share.

Get hold of a book found in Google Books:

Click (if available on the page) under Get this book in print on the link Find in a library. You will be directed to In this worldwide catalogue you can see if the book is available in the collection of Utrecht University Library or in other libraries around the world.

As in other Google sites there are clear differences between the .nl version:

  • Ranking: the Dutch version puts books in the Dutch language higher in the results list, and the other way around! This is especially the case in searching for proper names that are equal in both languages.
  • Subject terms: in the .com version you can also search by subject/keywords, 
  • Bookshop links: the Dutch version also contains links to Dutch bookshops.
  • Google eBooks: the Dutch version has the option to restrict to "Google eBooks". We advise you to always select "any books".

If you are searching on a particular topic, performing a search in the full text of books can be very convenient. With millions of scanned books Google Books is the best known full text database

Other useful search engines:

Articles published as chapters in books (edited volumes, readers) are not always easy to find.
The easiest way is, of course, to find the (e-)book the chapter is published in. 

In many search systems you can also search for book chapters by using filters and limits.
Usually the system will offer you filters after you have performed a search, but sometimes it is also possible to add limits beforehand (Tip: take a look at the Advanced Search options).

For example

  • WorldCat: filter on document type 'Chapter';
  • Scopus en Web of Science: filters (limits) on document type 'Book Chapter(s)';
  • Subject specific databases: filter on publication type, often: 'Chapter' or 'Book Chapter'.
  • With Google Books you often search the full text of books. In this way you might find out if or that an article or chapter is in a particular book.

Take your time to look for possible filters (or 'limits') for document types in other multi disciplinary search systems like Scopus and Web of Science or in subject related search systems (often called: 'Chapter' or 'Book Chapter').

Below a few tips for searching for book reviews:

  • Visit the page Search engines at the Utrecht University Library and limit/filter on publication type: ' (Book) Reviews'
  • Book reviews in newspapers can be found in Nexis Uni 
  • Or if you want to find book reviews  from Dutch newspapers before 1995, visit Delpher
  • You can also try to search a book by its title in combination with the word 'review' or 'book review'

Where to look for grey literature?

There are documents that are not available through the regular (publisher's) channels and that often do not have an ISBN or ISSN number. These documents (such as policy documents, reports, theses and dissertations, conference papers, pamphlets, etc.) are referred to as grey literature.

Searching for these types of resources is not easy. Grey literature can be found everywhere on the internet (at the government websites, at the webpages of organizations and companies, in databases, etc.).


  • Are you looking for policy documents, try Overton or the free database Policy Commons (make your own account).
  • Use Google to search for websites of companies, organizations and institutions that publish documents in your subject area.
  • Use the Netherlands Research Portal (Open Aire) for searching Dutch dissertations.

Many organizations place the reports they publish on their own website. These publications are often freely accessible and can be found via major web search engines such as Google or Bing.
You can use the following tips when searching for reports:

File type filter: Search with terms that describe your subject and set the filter for file type: climate change filetype: PDF (via the 'advanced search' screen). This decimates the number of results and limits it to the more important sources.
Site filter: If you know which organization publishes important reports for you, you can also set a filter 'site:' where you enter the domain name of the website, for example: climate change (for the United Nations environmental program).

 Filters gebruiken voor rapporten zoeken in Google
Report keywords: If you still find too many results, you can add that you are looking for reports. For example, add to your search: report OR investigation.

Some publications appear in the form of preprints or working papers (versions of scientific publications that have not yet been officially released). This type of publication is often available earlier and usually free of charge to everyone. Please note: the preprint/working paper may differ from the final (officially published) version.

You can find this type of publications by clicking 'All versions' in a search result in Google Scholar. There are also databases that offer preprints or working papers (see e.g. Dimensions (limit on publication type>preprints), SSRN (for social sciences, in a very broad sense), various preprint servers, etc., etc.)

Conference proceedings are collections of papers (or the summaries of these papers) presented at a conference. They often present preliminary research results and (as a collection) and offer a good overview of the state of affairs in a particular research area (and at that time).

It is difficult to trace (articles in) conference proceedings. Sometimes they appear in book form or as a special issue of a journal. You can find them in search engines and databases such as Google Scholar, Scopus or Web of Science.

If you are looking for an article in a collection of conference proceedings:

  • Enter a specific term in Google Scholar and enter conference proceedings at Advanced Search > Return articles published in:
  • You can search a database (a multidisciplinary one or one that is related to the field of the conference) and then (if possible) filter on conference abstracts or conference proceedings.
  • Some proceedings are available in print and can be found in WorldCat  on the title of the conference.
  • Look for the conference website, you may find the papers/abstracts, details for conference proceedings or other useful information there.

To 'How to search?'

Open Access search engines

Open AccessOpen Access articles are freely available. Below you will find a list of search engines containing only or mainly Open Access material

If you want to find out what journals are Open Access you can check the Directory of Open Access Journals
And use the Lean Library extension, it will tell you if an open access version of the article is available.

If the Utrecht University Library doesn't have it?

  1. Check WorldCat to see if the article or book is available, and if not, if it can be requested from another Dutch library or foreign library. Material from other libraries can be requested via WorldCat. Under Availability > Libraries Worldwide you will find the button Interlibrary Request.
  2. Is there an open access copy (author version) available (search Google)?
  3. Ask the author to send you the article/chapter. On publishers' sites and in search engines such as Scopus you will often find the email addresses of authors.
  4. Twitter to the rescue: tweet your request together with the URL and add the hashtag #icanhazpdf

Differences in search systems

There are many different search engines, you will have to make a choice before you start your search. But these search systems may differ widely in their search results. It is good to know where these differences originate from.

Even if you enter the same search question, the results in search engines may differ because of:

  • the coverage: what material is included:
    • is it a subject specific database (which disciplines/topics)?
    • or is it a multidisciplinary database (are there any accents on certain topics)?
    •  what years (publication  years/ historical periods)?
    •  what languages (most databases focus on English)?
    •  what kind of publications? (journal(article)s, books, websites)?
      • Every element of those publications (for instance also the book reviews in journals or the chapters in books)?
    • which of a certain kind of publication (which journals precisely)?
  •  the indexing depth: are you searching by:
    • only words from the title and the author's name?
    • keywords also, added by the author?
    • the summaries/abstracts also?
    • the full text?
    • extra keywords added by the makers of the database?
  •  the choice of search fields: most search engines let you decide what fields to search, but sometimes differ in the choices they offer. Search engines for journal articles often offer the default option: title/abstract/keywords. Under advanced search you will find more options.
  •  (relevance) ranking: in what order are the results shown:
    • by year of publication (most recent first or the oldest first)?
    • based on relevancy (the publications that best answer your question are shown on top)
    • based on frequency of the terms (the more often a term occurs, the higher the ranking in the list of results)?
    • based on the number of citations?
    • based on popularity (the more often a source is viewed, the higher the ranking)?
    • by the position of the terms in the source (for instance words from the title are more important than words from the text)?
    • in a mixture of the items above?
  •  the default treatment of your search terms
    •  must all search terms occur or is it also fine if only 3 of the 4 search terms occur?
    • are related terms automatically included?
    • are terms strongly resembling your search terms automatically included?
    • are terms that are related automatically included ?
    • are terms strongly resembling your search terms automatically included?
    • are terms with slightly different endings (singular/plural, verbs) automatically included?
    • how does the search engine interpret search terms put between inverted commas? ("exact phrase")
  •  Is there deduplication of (strongly resembling) search results?

Some of the questions above can be answered rather easily, for other you need to get to know the database a little better.