Combining search terms

PubMed has an advanced search interface. You can reach it via Advanced right below the search box. The advanced search interface consists of PubMed Advanced Search Builder and History and Search Details.

In the builder you can add search terms to the Query box. From there you can run a search strategy in PubMed. Searches from the History can also be added to the Query box to be combined with other searches.

Watch the Advanced Search Builder demo (2:06) below by Laupus Health Sciences Library (East Carolina University).

Use boolean operators to combine searches, for example to complete a search concept by combining MeSH terms with searches for words in the title and abstract ([tiab] searches).

OR
  Use OR to find publications that match one or both search terms. OR is used to widen your search (OR=mORe).
Example: diabetes mellitus[mesh] OR diabetes[tiab]

AND
  Use AND to find publications that match both search terms.
When looking for articles on gene therapy for diabetes, use:
diabetes mellitus[mesh] AND genetic therapy[mesh] or even better:
(diabetes mellitus[mesh] OR diabetes[tiab]) AND (genetic therapy[mesh] OR gene therapy[tiab]).
When combining AND and OR, make sure that the ( ) are correctly placed. Searching with (diabetes mellitus[mesh] OR (diabetes[tiab] AND genetic therapy[mesh]) OR gene therapy[tiab]) gives a very different result...

NOT
   With NOT all publications that match a certain term are excluded.
If you are looking for articles on diabetes, but not gestational diabetes, you could enter: diabetes mellitus[mesh] NOT gestational diabetes[mesh].
Note that articles on both types of diabetes will also be excluded.

When you split your research question into different subtopics, you can first look them up separately in PubMed. Suppose you want to find information about the best technique to give a subcutaneous injection to children.

First put a subtopic in the Query Box, and click on 'Add to history' under the menu at Search. This way you will not leave this screen, but you will see how many results the first sub-topic yields.

Using this technique, you can add the various sub-topics to the History. You may get a lot of results with a general topic like 'technique'. You can then choose to also try a search in which those search terms must necessarily appear in the title or abstract of an article.

Then click on the ... of the subtopics you want to combine. Click on 'Add to Query' in the first sub-topic and then on 'Add with AND'.

Your complete search string is now being built up in the Query Box. When you have added all subtopics, click on 'Search' next to Add to History and you will be taken to the results list.

You've now successfully combined searches!