Key word searches always look for all of the search words,
ie- Boolean "AND".
The exact keyword search looks only for exact matches in the argument (not
the rebuttal), and it ignores commonly used words and search terms shorter than 4
letters. The normal search will accept partial word matches and any search terms,
and it will search both the arguments and rebuttals.
If you search without entering any keywords, the system will produce
a complete list of all the arguments in the database.