Google Patents searches over 7 million patents granted by the United States Patent and Trademark Office (USPTO) as well as patent applications submitted to the office. Advanced Search allows searching of the individual parts of the patent, such as the patent number, inventor and assignee. The best patent searches include the USPTO classification code(s). (See the McKinney Engineering Library (University of Texas) and the Physical and Mathematical Sciences Library (Penn State) tutorials below for more on searching strategies.)
Patent search page: http://www.uspto.gov/patents/process/search/
Patents from 1976 forward are easiest to find because they are full text searchable. Patents prior to 1976 can be searched only by patent number and/or classification codes. Deciphering the classification codes for pre-1976 patents for pharmaceutical requires knowledge of chemistry and is best left to an expert patent searcher.
Here are some tutorials about researching patents using the USPTO's databases:
Page last updated: 8/2/2016