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Patents, Inventors and Entrepreneurship: How to search

A guide designed for engineers

Search Strategy

  1. Search by keyword. Be sure to try synonyms.
  2. Select examples of relevant patents and note all of the classes/subclasses.
  3. Look at cited patents and patents that cite this patent in the future and note all of the classes/subclasses.
  4. Search by the identified classes/subclasses to find other similar patents.
  5. Iterate – repeat this search strategy on the new patents you find.

Key tool comparison table

    Patsnap [MIT only] FreePatentsOnline Espacenet USPTO

    Create a free account to access the full subscription features.



    Free access with limited functionality and advertisments. 

    Free registration  offers additional functionality (e.g. PDFs viewing) and eliminates ads.

    Free from European Patent office.

    Free from the US Patent & Trademark Office
    US coverage

    1800 - Current. Includes both issued patents and applications.  Searchable from 1920-

    1836-current; only selected pre-1976 patents are full-text searchable

    1836 - current.  Abstracts from 1970-

    1790-current; pre-1976 can only search by patent # and class code

    Foreign coverage

    See also:

    Directory of Intellectual Property Offices by Country

    Europe 1976- ; China 1980- ; Japan 1976- ; Korea 1983- ; Taiwan 2003- ; WIPO 1978-. Additional European national databases recently added.   Only recent years are searchable for some national databases.

    EPO (Europe+) 1981-; WIPO 1978-; Japanese 1976-

    EPO (Europe+) 1981-; WIPO 1978-;


    Search interface Includes field and command line searching, as well as bulk download for known patent numbers. Features extensive browse, sort and filter options.  Includes proximity searching, word weighting, word stemming and presents results by relevancy ranking Offers 3 search modes:  Smart, Advanced, & Class.  Includes onscreen syntax and search tips.   Awkward; must follow complex syntax; but includes detailed  Help menu


    Yes, but registration required to view


    No; requires TIFF viewer for images





    Yes, in separate database

    RSS/email alerts






    • Patent application status

    • Data analysis and visualization tools

    • Image thumbnails with zoom function in results

    Registration required for advanced features such as saving searches, email alerts, viewing PDFs, etc.

    *   Links to browsable online CPC classificaiton guide.

    *   Interface available in multiple languates with links to numerous national patent databases.

    • Patent application status

    • Assignee changes

    • Sequence searching available