AND narrows down your search results to those which contain only these terms.
OR expands your search.
NOT eliminates unrelated records from your search results.
Truncation ( * ) allows you to search for multiple word endings in one search. Place an * at the end of the word root to obtain more search results.
Example:
Environ* = Searches for any text containing environment, environmental, environ, environs, etc.
Quotation Marks (" ") allow you to narrow your search to an exact phrase.
Example:
"Sir Gawain and the Green Knight" = Searches for that exact phrase.
Wildcards (?) allow you to search for variant spellings within a word in one search.
Example:
Wom?n = Searches for woman or women