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) |

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