Patents are a rich source of engineering information. Google Patent Search covers the entire collection of granted patents and published patent applications from the USPTO, EPO, and WIPO. US patent documents date back to 1790, EPO and WIPO to 1978.

Use Google Patent's Advanced Patents search page to search by criteria such as patent number, inventor, classification, and filing date.

Search for prior art by clicking on the "Find Prior Art" button from a patent's main page, or on the "Related" link in patent search results.

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