EBM Literature Sources : 2. Embase

The database EMBASE is the European counterpart of MEDLINE and contains over 32 million references from more than 8500 biomedical journals published in 95 countries.Coverage runs from 1947 onwards. In EMBASE you will find more European and pharmacological references than in MEDLINE, besides conference abstracts. More than 6 million references in 2900 journals are unique to EMBASE.

Elsevier's search engine Embase searches both the EMBASE database and the indexed articles in MEDLINE.

In the boxes on this page you will find information about searching in Embase:

• Searching in title/abstract/author keywords
• Searching with the help of keywords
• Combining searches
• Tips & Tricks

The MEDLINE database is searched by PubMed as well as Embase. In addition, Embase searches the EMBASE database.

So is there any point in using both search engines in a search?

Yes, there is, because:

1. PubMed also searches the newest references which have not been included in MEDLINE yet because they have not been indexed yet. You won't find these in Embase

2. In Embase you will find the unique references which are in EMBASE, but not in MEDLINE. This involves more than 6 million references and 2900 journals.

All references in Embase are labelled: Embase, MEDLINE or both. References with a MEDLINE label are most likely already in your PubMed search. References with an Embase and MEDLINE label are present in both databases, but due to differences in indexing, new results may show up here as well. The majority of the 7410 in the example below will be duplicates. References wiht only an Embase label are not present in PubMed so will be new additions to your search. You can select which set you would like  to use by clicking on the corresponding areas in the graph under 'Sources'.

In  ‘Advanced Search’  you can indicate whether Embase should search in EMBASE, in MEDLINE or in both. If you have already done a search in PubMed, you can safely exclude references that only occur in MEDLINE.

• In Embase it is not possible to export more than 10,000 search results at once to, for instance, Endnote. For RefWorks there is even a maximum of 500 results at a time. If you have more search results, you can limit the results on ‘Publication year’ (for instance. 2000-2005 and 2006-2010) with the help of the option ‘Filters’ (to the left of the search results). In this way it is still possible to export all of your search results in two or more times. Another alternative is to export your results (with a maximum of 10,000) in one go as RIS file (the first option in the Export screen), save them and then import them into RefWorks separately..
• Via Embase you will also find the publication type 'Conference Abstracts'. These are abstracts published in special issues, supplements. For a full review of the literature, you can include the last two years of abstract in the screening. These can be from studies that are still ongoing, or otherwise not yet published. Depending on the topic, Conference Abstracts may take up 50% of the total results. So for a quick review, it can be easier to filter them out. To do so, add the filter via the menu on the left. If you first select only the Conference Abstracts, and click Apply. The filter is added and you'll only see Conference Abstracts. Now change the AND for a NOT and you've excluded them. See below, were #5 was your final search.

Just like in PubMed, you have to search for search terms (and variants) and keywords in Embase.

You can search in Embase in title / abstract / author keywords by choosing 'Title, Abstract, Author keywords' in the drop-down menu at Quick search.

Then you add with the Boolean operator 'OR' keywords from EMBASE (= EMTREE). See the example.

• A PubMed search with [Title / Abstract] also searches by default the keywords that authors have added to their article.
• These keywords do not have to be the same as the mandatory indexed keywords (or thesaurus words) such as Emtree or MeSH terms.

Via 'advanced search' you can also construct your own search: e.g.:

sarcoidosis: ti,ab,kw OR 'besnier boeck':ti,ab,kw OR 'schaumann disease':ti,ab,kw..... but don't forget to put quotation marks with frases(red!)

Via Quick search, these quotation marks are placed automatically!

• Embase uses single instead of double quotation marks - so, for example, search for ‘amyotrophic lateral sclerosis’ and not, as in PubMed, on "amyotrophic lateral sclerosis". The use of an apostrophe (eg, Alzheimer's) gives an error message in Embase - you can solve this by using ‘Alzheimer / s’ (including quotes) or use a asterisk, see below ↓
• As in PubMed, you can use an asterisk (*) in Embase to search for multiple word variations simultaneously (truncation). Put the asterisk within the quotes, e.g.: 'operative procedure*':ti,ab,kw. This will also retrieve  'operative procedures'. For the problem above: Alzheimer*:ti,ab,kw

The keywords in Embase are called Emtree terms. Compared to PubMed more keywords are assigned per article in Embase, in particular keywords relating to pharmacology and pharmacotherapy.

To search by keywords in Embase click on Emtree (1) in the drop-down menu under  'Browse' in the blue bar at the top of the Embase screen.

To find keywords, enter a search term in the Emtree search bar and click on ‘Find Term’ (2). Next you click on one of the displayed options (3).

In the next screen you will see the position of the term in the hierarchic structure of keywords. As a rule, all underlying keywords are considered as well (‘Explosion’; you can choose to switch off this option (4). Click on ‘Add to Query Builder’ (5) and next on Search’ (6) to search Embase.

NB: All MeSH terms are included in the Emtree database, although sometimes under a different name. If you search for a MeSH term in the way shown above, you will be automatically referred to the matching Emtree terms. Do not forget to check if it is really the term you want to use!