esp@cenet International patent database containing 60+ million patents from more than 70 national and regional patent offices. The full text images of the documents in Espacenet are available as PDF files. Online tutorials for esp@cenet searching are available here.
Canadian Intellectual Property Office (CIPO) Patent Database
Canadian patent records, 1869 to present; full-text documents, 1920 to present.
This database contains patent documents from 1869 to the present. This database is updated regularly with newly granted patents and applications opened to public inspection. The electronically available patent information consists of patent document images and bibliographic and text data.
U.S. Patent Office
U.S. patents, 1790 to present and published applications, 2001 to present. Patents prior to 1976 can be retrieved by number, date and classification. TIFF viewer
required to view/print patent documents. General overview
of the U.S. patent system.
Free Patents On Line
FreePatentsOnline.com provides fast, easy-to-use and free access to millions of patents and patent applications from the United States, Europe, Japan, and WIPO.
Searchable full text/full page images of U.S. patents from USPTO. It is an alternative interface to searching USPTO.
Japan Patent Office
The Japan Patent Office (JPO) is responsible for the protection of the rights for patents for inventions, utility models for devices, industrial designs, and trademarks in Japan.
How to search for patents
Patent tutorials by Michael White , Science Librarian, Queen's University Library. Excellent introduction on how to search for patents by subject , read patent numbers.