Enable Keyword, Title, Author Searches of Z39.50 Servers

It would be very helpful when trying to copy catalog older books without ISBN, ISSN, etc. to be able to simply search by Keyword, Title, Author. This sort of searching would also require there to be a command to limit how many results my searches retrieve, and it would probably even require that I only be able to search one Z39.50 server at a time so as to prevent redundant search results, but it would be far more efficient than manually cataloging every book published before 1970 by hand.