There are other indices available that have some secondary importance to Chemistry. I have listed a few of them, note that this is not a complete list. If you have a chemistry-related search check with the Reference Desk or read the list of indices available. Most of these indices are bibliographic, i.e., references only. Both of these provide access to most North American doctoral dissertations, with some European universities being added recently.
Dissertations are an excellent source of information and further references.
RUL interlibrary loan will borrow these dissertations from the respective libraries, however they can take several weeks to arrive. Medline Medline is a good database for chemical information relating to medical science, including pharmacology, biochemical and biotechnology. It is one of the few indices that allows searching by CAS registry number. The coverage is excellent and includes material from the mid-60s onward. CAB - Cambridge Abstracts Includes references to all life science material.