U.S. Master Classification File (MCF) / Patent Grant (Patent Grant Sequence) (1790 - April 2018)
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资源简介：
Current U.S. classification information for all patent grants issued by the U.S. Patent and Trademark Office from 1790 to May 2018. Approximately 450 main divisions of technology, called classifications/classes, broken into approximately 150,000 subdivisions, called subclassifications/subclasses.
