Boolean Operators

The Boolean logical operators AND, OR, NOT, NEAR and NEXT can be used to combine search terms or query numbers in a variety of ways:

depression AND tricyclic - Both words must be present in each record

aged OR elderly OR geriatric - At least one word must be mentioned in each record

aids NOT audiovisual - Aids must be present but audiovisual must be excluded

Boolean operators can be combined and nested with parentheses within a single search statement:

(aged OR elderly OR geriatric) AND (depression OR insomnia)

    NEAR/n requests terms that are within n words of each other, in either order. For example, symptom NEAR/5 headache retrieves records with at most 4 words between the search terms symptom and headache (in either order).

    NEXT/n requests terms that are within n words of each other, in the order specified.

    • The proximity operators NEAR and NEXT can be used with parentheses, truncation and field limits, for example: (symptom* NEAR/5 (headache* OR ‘head ache’)):TI,AB

     

    Notes

    • If no other operator is specified, AND is the default operator;  heart failure is searched as heart AND failure if not enclosed in quotation marks.
    • Boolean operators can be used in any search form, including Quick Search.