Step 1: Brainstorm keywords, including synonyms and equivalent terms, to describe the invention.
Step 2: Search the keywords in a patent database to find the classification (class and subclass) of the invention.
Step 3: Use the class and subclass to search for similar patents and patent applications. Keep track of useful and non-useful patents (by patent number) to avoid duplication of efforts.
Step 4: Consult the cited references in the patents you retrieved to find additional related patents.
The Candian Intellectual Property Office's (CIPO) Canadian Patents Database provides access to patent descriptions and images from 1869 to present. You can search, retrieve and study more than 2,180,000 patent documents.
Consult the help page for search tips.
The U.S. Patent & Trademark Office (USPTO) Patent Database includes full text for patents issued from 1976 to the present and PDF images for all patents from 1790 to the present.
The DNA Patent Database (DPD) contains a collection of DNA-based patents and patent applications issued by the USPTO. It contains patents from 1971 to the present and patent applications from 2001 to the present.
DOEpatents, developed by the U.S. Department of Energy (DOE) Office of Scientific and Technical Information (OSTI), is a searchable database of patent information resulting from DOE-sponsored research and development (R&D). The database contains patent information from DOE R&D, historic and current, excluding patent applications.
Watch the tutorial from the US Patent and Trademark Office on the patent search process. The Seven Steps in a Preliminary Search of U.S. Patents and Published Patent Applications (PDF handout).
Adapted from UCSD Library's Patent Guide (with permission)
Espacenet, the European Patent Office's (EPO) database, offers free access to more than 100 million patent documents worldwide, containing information about inventions and technical developments from 1836 to today.
Adapted from UCSD Library's Patent Guide (with permission).
Chemical Abstracts Service (CAS) indexes chemical patents from approximately 25 countries and patent organizations in SciFinder Scholar (account registration required).
Consult the Scifinder How To Guides to watch tutorials on searching in SciFinder.
The in-depth patent information in Reaxys covers patents from 1976 to the present in organic, inorganic, and organometallic chemistry.
For more information on chemistry patents, visit the American Chemical Society's Committee on Patents and Related Matters website.
Google's patent search site. Contains US, EPO, and WIPO patent documents.