This is a little simplistic, but explains why patents are factual, unique from other research resources, and a little vague in certain specifics. This article first addresses the most useful free databases, then describes national patent agency resources, commercial patent databases, then other commercial services. At the end of this article, we describe patent classification and patent search strategy. The IBM's Patent Server is a public service providing a different patent database of US Patent abstracts. Abstracts are not provided.
Descriptive info is here .
Consider also the Internet Patent Search System . As you now know, patent.uspto.gov also delivers abstract retrieval, but I like the more minimal title lists here. Patent libraries are an important and cost-effective patent resource. Staff will help you use the APAS database, arranged for free text searching by International Patent Classification. You will need the patent number, country and title for this.