Type AND between your keywords to narrow your search. The database or search engine will only retrieve those articles or web pages that contain both words. Using AND will decrease the number or hits or articles or web pages in your result list.
Example: school AND crime
Note: Some databases and search engines (such as Google and Craigslist) allow you to type a plus sign (+) in front of a keyword when doing a basic search. This works the same as AND.
Example: +school +crime
OR Type OR between your keywords to broaden your search. The database or search engine will retrieve those articles or web pages that contain at least one of these words. Using OR will increase the number of articles or web pages in your result list (especially if not used in combination with AND or NOT). Use OR between keywords that are synonyms or have similar meanings.
Example: baby OR infant
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
Truncation, also known as stemming, uses a character such as asterisk (*) or question mark (?) at the end of a word, which allows you to search for a root form of a word and pick up any ending.
Example: typing teen* will find teen, teens, teenage, teenager, teenagers.
Wildcard symbols can be typed in place of a letter or letters within a keyword if you are not sure of the spelling or if there are different forms of the root word.
Example: wom?n will find both women and woman.
Note: Again, check the Help or Tips links available on most library databases and Internet search engines to verify the wildcard symbol that should be used - usually an asterisk (*) or question mark (?)
To look for an exact phrase, use quotation marks (" ") around the keywords.
Example: "attention deficit disorder”
Note: this works in most search engines as well. If you type an exact phrase without quotations when doing a basic search, most search engines will look for each word separately. This means your result list will include web pages that not only contain the exact phrase (ex: attention deficit disorder) but also web pages that contain a word or words from the exact phrase appearing separately (ex: attention may appear in one paragraph or sentence and disorder will appear in another paragraph or sentence).
Other schools have put together demos and tutorials on various search techniques.