Chemical Patents Plus, an information retrieval service provided by Chemical Abstracts, is available via the Web. After registering, interested users can freely search and receive title and abstract information for chemical patents going back to 1971. Other options, such as patent number, front page and all claims, and complete patent, are fee based. The service is available from 6:00 p.m. Sunday through 10:00 p.m. Friday and from 3:00 a.m through 6:00 p.m. Saturday.