Boolean operators--OR, AND, NOT--are used between search terms to combine concepts in a more precise way than is possible with keyword searching.
|The AND operator narrows a search, retrieving only records containing both term(s). AND is used to narrow a topic to a specific aspect.|
Example: anorexia AND "college students"
|The OR operator broadens a search, retrieving records that contain either term, but not necessarily both. It is used to combine synonyms or related concepts.|
Example: anorexia OR bulimia
|The NOT operator also narrows a search by removing all records that contain a particular word or phrase.|
Example: anorexia NOT bulimia
The NOT operator is rarely used. It often screens out useful records.