Use Boolean operators (AND, OR, NOT) to combine keywords in a search.
1. Use AND to narrow a search. Both and/or all search terms must be present in all references retrieved. Example: global warming AND forests
2. Use OR to expand a search. Your search will retrieve records with EITHER of the terms. OR is most often used to combine synonyms or like terms.
Example: hyperactivity AND children or adolescents
3. Use NOT to exclude a term. Records with the first term will be retrieved, but any records with the second term will be eliminated.
Example: eating disorders NOT bulimia
Nesting is using parentheses ( ) to insure that Boolean operations are performed in the sequence you intend. Nesting synonyms can broaden your search. Nesting is typically used when you have only one search box.
Example:
will retrieve both of the following: Smoking is on the rise in teenagers Adolescents turn to smoking to relieve stress