Google PatentsIncludes over 4 million patent applications and over 10 million granted patents from the United States Patent and Trademark Office (USPTO), European Patent Office (EPO), World Intellectual Property Organization (WIPO), Deutsches Patent und Markenamt (DPMA), Canadian Intellectual Property Office (CIPO), and China's State Intellectual Property Office (SIPO). Quick access to images (thumbnails and full size); downloadable PDFs; Google search features; full text of older patents; links to "prior art" and Ask Patents.