Google Patent Search (beta)
Shows thumbnails of patent drawings automatically and displays each patent in a comprehensive layout that makes researching very simple. Includes the text of every patent, even those granted prior to 1976, and the text is searchable. This is a key difference from the USPTO database.
freepatentsonline
Offers either a USPTO-style search or a search via a simple structured menu. Permits you to print an entire PDF of a patent in one click (unlike the USPTO site, where you can only print one page at a time). Also allows you to search the granted patent, patent application, and European patent databases simultaneously.
Protecting Your Research Data