Original source: United States Patent and Trademark Office. USPTO Patent Full-Text and Image Database. < http://patft.uspto.gov/netahtml/PTO/search-bool.html > accessed January 2008. Ancestry.com has searchable indexes; database results and some digitized images are available with a fee-based subscription. Free articles and helpful research materials.
The full-text database contains all the 6.5 million US patents issued since 1790. In the form of searchable patent numbers and current US classifications hyperlinked to full-page images of each page of each patent.