Type NOT before a keyword to exclude that keyword from your search. Using NOT will decrease the number of articles or web pages in your result list. The best use of NOT is when you are searching for a keyword that may have multiple meanings.
Example: bat NOT baseball
Use parentheses ( ) to keep combination searches in order. In the example below, the database or search engine will retrieve articles or web pages that must contain the word law and at least one of the words in parentheses.
Example: (ecstasy OR mdma) AND law
Other schools have put together demos and tutorials on various search techniques.
Look for the database's Help page. There is usually a link to the Help section of each database (e.g., Look for: Help, Tips, FAQ, Advanced Search). They usually provide good examples of how to search. You can always ask a librarian as well.