Training New PubMed (EN): 3. Advanced search

The default search in PubMed is both on the literally entered search terms in all fields, and the MeSH terms. You can edit the default search of PubMed by indicating the search fields yourself. Some options are: author name [au], journal title [jt] and title/abstract [Title/Abstract]. Title/Abstract searching also includes searching for author keywords! In addition to [Title/Abstract] you can also use [tiab] to search in the Title/Abstract.

List of all searchable fields and their meanings

Behind the search term you can put the fieldname between square brackets yourself. To this end you can also use the 'PubMed's Advanced Search Builder' under ‘Advanced’.

Using the 'Builder' you can indicate for each search term in what field(s) must be searched. Default setting is 'All Fields', but you can change this yourself in a preferred field.

To build a search, you can enter a search term in each line of the 'Builder' (and select in what field the term must be searched). The entered search terms appears automatically in the search line at the top of the screen. You can click on to add this part to the query box.

For each new search term you indicate how you want them combined with the previously added search terms: with AND, OR or NOT (for more explanation see the box 'Combining search terms' below.)

Finally, you click on 'Search' or 'Add to history' to perform the search. If you select 'Search' you will go to the screen with search results. If you select 'Add to history" you will remain in the 'Advanced search' screen where you can immediately perform a new search or combine searches (more on this subject in the box History and Search Details).

To find words with different endings or alternative spellings you can use the truncation symbol: an asterisk (*). In that case PubMed searches on all words and word combinations starting with the letters in question. For instance: obes* searches both on the word 'obese' as on the words 'obesitas', 'obesity' and all other words and word combinations starting with 'obes'.

Tip: Go to the 'Advanced Search' within PubMed and select to search within 'Title/Abstract'. Write down the truncated word, in our case 'obes', within the search bar and click on the 'Show index' button. The 'Show index' button will show you the word variations that are possible with this truncated word, which will help you find the best spot to truncate a word.

Note 1: You can only put an asterisk at the end of a phrase or word that has a minimum of 4 characters.

Note 2: You only can put an asterisk at the end of a phrase or word. Don't use h*ematology for instance, to find British and American spellings!

In PubMed you can combine search terms with the help of the so-called Boolean operators OR, AND, and NOT. With OR, PubMed searches for results in which one or both search terms occur (fig. 1 below). If you combine two search terms with AND, PubMed will only search for results in which both search terms occur (fig.2).  NOT produces all results in which the first term occurs, but the second does not (fig.3).

If you want to combine more than two search terms we recommend using brackets. Without brackets PubMed carries out the commands OR, AND and NOT in the order in which they are entered. This may give unwanted results!!

Suppose you are looking for articles about vaccination against swine flue. If you set up your search as follows:

vaccination AND swine flu OR H1N1

You will find articles in which the words 'vaccination' and 'swine flu'  both occur, as well as articles in which the term 'H1N1' occurs (but which do not necessarily have to be about vaccination). 

So the right way to formulate your search is:

vaccination AND (swine flu OR H1N1)