Regional libraries with Patent and Trademark Resource Centers (PTRC), part of a nationwide network of public, state, and academic libraries designated by the USPTO to support the public with trademark and patent assistance.
Regional Library List
Linda Hall Library, Kansas City, Missouri
Ablah Library, Wichita State University, Kansas
Links to major patent search engines are listed here. The USPTO will be the most authoritative source for United States patents and patent applications while other sites might offer an easier to user interface.