The simple search allows two terms which you can limit to specific data fields. There's also an advanced boolean search. Simple and advanced full-text searches are also offered. Here's a pretty cool site from the Intellectual Property Office of Singapore. The advanced search doesn't include the business news and Web search, but allows you to focus your search on an individual's name, assignee or other qualifiers.
Registration is optional.
This site offers links to Worldwide Patent offices, some with searchable databases. The U.S. Copyright Office offers a searchable database. I highly recommend reading the instructions before attempting a connection and search. Copyright 2001 Internet Prospector Inc.