Most databases and major search engines support complex Boolean searches. If you have a complex search using more than one operator, you can nest your search terms by using parentheses. Search terms and operators included in parentheses will be searched first, then terms and operators outside the parentheses. A search for:
(ADD OR attention deficit disorder) AND college students
will search the exact phrase, e.g.: "date fruit"
Word stemming can be used to search for a portion of a word with a variant ending.
If you searched for therap* you would return results that included therapy, therapist, therapeutic, therapists and any other word that started with the letters therap before the truncation symbol.
Be careful not to truncate too far, or you will retrieve unrelated words!
Before you do any of the database searching, learn about Boolean Logic:
The examples above illustrate general topics expressed with just two keywords. Actual search strings, which express complex topic ideas, may consist of several keywords and combinations of Boolean operators.
The thesis statement "Automobile air bags are not safe for children" might result in the search string:
automobiles AND air bags AND children AND safety