You can use additional techniques to further expand or limit search results
Use quotation marks around a phrase (not a single word) or select "as a phrase" in a pull-down menu.
Use parentheses ( ) to nest related search terms.
Example: (bay OR harbor) AND pollution
Use a symbol to search variations of root words
Truncation symbols vary from database to database - an asterisk (*) is the most common truncation symbol.
Many databases give you options to limit search results by: document type, publication date, language, etc.