By Default keyword searches are 'AND' searches, which means that each word or group of words submitted must all be present in all of the files that it finds.
George Bush will return all the files that have 'George' and 'Bush', although the string "George Bush" may never appear in the story.
Exact Phrases
Place double quote marks (") around any phrase of words to find exact phrases.
"George Bush" will query only for files with the string 'George Bush' in them.
"George Bush","John Kerry" will query only for files with the string 'George Bush' AND the string 'John Kerry' in them.
Negate words/phrases
To negate a word or phrase from search results, place a dash (-) at the beginning of the word or phrase. The results will query only for files that contain the query word(s) but NOT the negated word.
'George Bush', -'John Kerry' will query for all files with the string 'George Bush' that do NOT contain the phrase 'John Kerry'.