- US Patent and Trademark Office
Search US granted patents for free. Downloading patents, searching international patents, and searching US and international patent applications is fee based.
With patent number, retrieve Adobe PDF version of U.S. patents (easier than using USPTO).
- UK Patent Office
- esp@cenet (European Patent Office)
Search patents worldwide
- WIPO (World Intellectual Property Organization)
Search international patent applications
- Google Advanced Patent Search
- Information on Patents for Researchers
Guide from the University of Pennsylvania's Science and Engineering Library.
- Patent Analysis Free Databases
Patent Analysis provides free access to the US patent databases, EU patent databases and the WO/PCT patent database. Users must create an account.