Combining search terms – Boolean operators

Most search engines and databases support the use of Boolean operators AND, OR and NOT. Usually these should be written in capital letters.

retrieves documents containing both terms.

2.2.2 Boolean_AND_orange

OR retrieves documents containing either term.

2.2.2 Boolean_OR_orange

NOT excludes the retrieval of terms from your search.

2.2.2 Boolean_NO_orange

You can group your search terms in parentheses to perform more advanced searches. A good way to structure you search is to think of the key concepts of your paper, and think of synonyms for each of these concepts. Group the synonyms in parentheses combined with the search operator OR, and then combine these groups with the search operator AND.

For example:
(congenital OR neonatal) AND Malaria AND Africa

2.2.2 Boolean_PARENTESIS_orange

Don’t forget to keep records of the keywords you used and the sources you consulted as well as references of all the items you are going to use.


Learn how to keep track on your search strategies on the next page.

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