Thus, a search for the same information using two different search sites may turn up different results. There are a relatively small number of top-level categories from which you can choose. Directories are most useful if you are looking to learn more about a subject. Search Indexed Sites Other sites offer the ability to locate information based on a word or words. These gather information from Web sites and create a database of words and phrases.
Boolean logic is explained in simple terms below.
The following rules apply to using the Advanced Search option of AltaVista. Please note, however, that many of these rules apply to other search engines that use indexes. Use the binary operators AND , OR , NEAR , and the unary operator NOT to combine words and phrases. NOT Use the NOT operator to eliminate a term. The NEAR operator can be substituted for the AND operator when the two words or operators should be located within eleven words of each other.