When you choose a search method, you are specifying how you want your search terms to appear in a document. You can choose Any Term, All Terms, Exact Phrase, Near, or Boolean. To choose a search method, simply click the down arrow in the Search Method box and click on the option you want.
Here are links to descriptions of each search method:
Using the ANY TERM search method
Using the ALL TERMS search method
Using the EXACT PHRASE search method
Using the BOOLEAN search method