Patents Patents Chemical Patents Plus Offers the full text for all classes of patents issued by the U.S. Patent and Trademark Office from 1975 to the present, including partial coverage from 1971-1974. Complete patent page images are available for patents issued from 1 January 1995. The first entries date back to January 5, 1971. This database now offers all U.S. patents issued since 1790, in the form of searchable patent numbers and current U.S. classifications, hyperlinked to full-page images of each page of each patent. U.S. Patents is a fully searchable bibliographic file containing all U.S. patents issued since 1975.
Emphasis is on tracing technological impact of existing patents.
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