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Patent resources: Finding patents

A collection of resources for searching and understanding patents

Finding US patents

The U.S. Patent & Trademark Office (USPTO) Patent Database includes full text of patents from 1790 - present and also provides TIFF images of most of them.

By Patent Number

  1. Go to USPTO Database.
  2. Select Patent Number Search or Publication Number Search.

By Subject

  1. Go to USPTO Database and select Quick Search. Enter keywords in the search box.
  2. Find a patent that is close to what you're looking for.
  3. Note the Cooperative Patent Classification (CPC) number/Subclass for that patent, e.g. A01D 711/111 .
  4. Do a search of that Class/Subclass in USPTO Database to find more patents on that subject.

OR ...

  1. Go to CPC Classification System Scheme and search for common terms or keywords.
  2. Use the Class/Subclass numbers you found to check the CPC Classification System Scheme to see if they are on target.
  3. Search by Class/Subclass numbers in USPTO Database. Make sure that you remove any spaces.

This is a helpful guide from the USPTO which uses their 7 Step Strategy with new CPC code system.

Finding international patents

The European Patent Office maintains a free database of worldwide patents (including U.S. patents) called Espacenet. Images of patents are provided in PDF format, but can only be printed one page at a time.

By Patent Number

  1. Go to Espacenet and enter the patent number (with or without the country code) in the Smart Search box.
  2. All documents with that number will be listed. 
  3. Choose the patent record you are looking for.

By Subject

  1. Go to Espacenet Advanced Search page and enter your keywords in the "Title or abstract" box.
  2. Find a patent that's close to what you're looking for.
  3. Note the International Classification number/Subclass for that patent, e.g. H04B1/59.
  4. Do a search of that Class/Subclass in the serch box at the Espacenet Classification Search page to find more patents on that subject.


Espacenet Tutorial - How to search esp@cenet, the European Patent Office's online patent database


See the Patent Websites tab for additional international patent databases.


Finding chemical patents

Chemical Abstracts Service (CAS) indexes chemical patents from approximately 25 countries and patent organizations. UCSD affiliates may search the online CAS database, Scifinder.

Once you have obtained access to SciFinder Scholar, go to Explore References

To search by patent number, assignee name or inventor name, select  Patent and enter the information you have. 

To search by subject, select Research Topic and limit to document type Patent.

Scifinder How To Guides


Contact Me

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Joseph Riggie
BUTL 155a

Useful links

  • Patent Workshops
    Patent workshops are offered quarterly for UCSD faculty and staff through Staff Education & Development.  If you are a student and wish to take this workshop, contact me at

  • Ask a Librarian
    Please don't hesitate to ask for assistance in finding information. That's what we're here for.
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