The search terms you use really determine your success. The words and operators you use to help you in your search can greatly improve or reduce the effectiveness of your searches. Boolean History Boolean logic is a symbolic logic system invented by mathematician George Boole. In 1849, Boole developed an algebra of logic, which has become the basis for computer database searches.
Boolean logic uses words called operators to determine whether a statement is true or false.
Most search engines including Yahoo, AltaVista Advanced Search, HotBot, and Excite can make use of Boolean operators. These operators are designed to put conditions on the keywords that you are searching for which can be a huge help when doing an online search. AND operators If you are looking for a document that should contain all of your keywords you can use the capitalized word AND between keywords and the engine will only return documents that have both words. AND, otherwise the search engine will treat it as a keyword, not as an operator. If the left circle represents all documents containing the word teacher and the right oval represents all documents containing the word technology , the intersection of those ovals, the blue area, represents all documents containing both words.