The two words school and violence. Those two words (regardless of capitalization) must occur somewhere in the index but not necessarily together or in any order. (Words separated by spaces are treated as if the space was an implied <and> operator.)

The words school violence together in that order anywhere in the entry, regardless of capitalization. (Multiple words enclosed by quotation marks are treated as a single search phrase.)

Either the word school or the word violence anywhere in the entry, including together, regardless of capitalization.

Documents containing either the phrase school violence or the word teens.