Introduction to Boolean Logic (continued)

AND:

• Used to retrieve a set in which each citation contains all search terms.

Example: salmonella AND hamburger

Note in the diagram to the right and in the sample search results below that the retrieval is only the overlap of the results for each term – those records in which both terms appear.

• AND is the default operator used in PubMed. If you do not include Boolean operators in your search, PubMed will automatically use AND between terms.

Example: diabetes mellitus phototherapy

PubMed searches as: diabetes mellitus AND phototherapy