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Boolean Logic

Connecting words such as AND, OR, NOT to expand or narrow a search.

AND

OR

NOT

Finds information containing both terms (A and B) —narrows the search

("Citrobacter rodentium") AND ("immune response")

Finds information containing either one or both of the search terms (A or B)—expanding the search results

Ex: (mouse OR mice OR murine)

Finds information that does not contain a term (A not B)—narrows the search

(pig OR porcine) NOT (guinea)

Connecting words such as AND, OR, NOT to expand or narrow a search.

rat* = rat, rats, ratio, ration, rationing, rate, Rattus