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Issues in Science and Technology Librarianship
Winter 2015

Science and Technology Resources on the Internet

Patent Searching for STEM Researchers

John J. Meier
Science Librarian
The Pennsylvania State University
University Park, Pennsylvania


Entrepreneurship and intellectual property (IP) management have become a focus of academic institutions over the past decade. This webliography is intended to help guide researchers and inventors to the patent information they need in order to advance science and protect their IP. The information landscape around patents has changed dramatically since the publication of the two previous patent webliographies (Kawakami 1998; LaCourse 2010). This guide will cover changes in patent information, updates to information sources and interfaces, and new patent information sources. Most databases covered are free to use, except where a subscription cost is noted. This webliography is intended for librarians and scientists already familiar with database searching, but with limited experience with patents and patent-specific databases.


Patent research used to involve lengthy paper indexes, microfilm, or custom software only available in a limited number of libraries. Patent information is now freely and easily available, and there are advanced searching tools available, either open access or through database subscription. Patent searching has also become necessary for more than just potential inventors looking for prior art or genealogists researching past innovators (Baldwin 2008). Many discoveries never reach the scientific record of journals and conference proceedings, instead finding their lone publication in patents. No matter the rationale for patent searching, there are key strategies that can be used and established sources for information that should be explored in any patent search.

Patent Searching

The main methods of patent searching are keyword searches, field searches and classification searches. Keyword searching of patents has become increasingly effective with more full-text searching available, but it is still limited by both the sheer number of patents and the technical jargon used in patent writing. Field searching is most effective for finding a known patent. Each "field," or bibliographic data element, of a patent is consistent across all patents, even across patent offices in different countries; inventors do not change, assignee (owner) is often a known company, and so on. Patent numbers are unique identifiers assigned when a patent is published and are standardized to the form CC 123456789 KK, where CC is the country code and KK is the kind code.

The most authoritative field to search is classification, or the technology area that the patent is grouped into by the issuing agency. Until 2015, all U.S. patents were assigned to one or more U.S. Patent Classification (USPC) categories, which were updated frequently due to changing technology or growing categories. While the USPC will still exist in older U.S. patents, it will no longer be updated or used for new patents. Now, the U.S. uses the Cooperative Patent Classification (CPC) system, which was developed over the past few years with other international patent offices. Details on both systems are available on the U.S. Patent and Trademark Office web site. The CPC is based on the older International Patent Classification (IPC), a common standard from the World Intellectual Property Office. The CPC system updates the IPC by making categories smaller, which improves search results and speeds searching. For more in-depth information, The Busy Librarian's Guide to Information Literacy in Science and Engineering has a chapter on how to conduct different types of patents searching (Meier 2012).

Patent Information Sources

The resources below were selected either for being primary sources (patent agencies), providing specialized search functions (free web sites and licensed databases), or for particular strength in a STEM field (such as chemistry).

US Patent and Trademark Office (USPTO)
The U.S. Patent and Trademark Office is the primary, authoritative source for United States patent information. They have separate search interfaces for issued patents (PatFT), applications (AppFT), and patent application documents (Public PAIR). The databases PatFT and AppFT have the same search interface. When performing searches, it is important to use proper formatting (look for the "Query Help" link for tips). For pre-1975 patents, PatFT is typically limited to searching by patent number, issue date, and U.S. Classification, but the USPTO has begun expanding coverage to earlier dates; you may find patents from the 1960s and 1970s in some areas, but you must change "Select Years" from the default 1976 to present. AppFT only covers applications since 2001. Patents and applications can be downloaded as PDF files by individual pages or as an entire document. Public PAIR is a unique resource for seeing correspondence between the USPTO and inventor, including reasons for the failure of an application.
European Patent Office (EPO) Espacenet
The European Patent Office's search engine Espacenet is the largest worldwide patent database, with over 80 million patents. With the adoption of the Cooperative Patent Classification (CPC) between the USPTO and EPO, Espacenet has added a searchable CPC index, browsable CPC, and CPC tutorials that make the database easy to use for classification searching. Since it includes patents from multiple countries, including the U.S., the European Union (EU), and many Asian countries, Espacenet is truly a "worldwide" search interface. Keyword searches can be done in the "Smart search" or by field under "Advanced search". Due to international standardization of patents, it is more limited in number of searchable fields compared to USPTO's PatFT, but it does cover most key search terms. Results are limited to the first 500 hits, so savvy searching and limiting results is important. Patents are available as PDF files in their language of publication, but the abstracts and other bibliographic information are machine translated into multiple languages, including English. Espacenet also collects patent families, which are groups of patents and applications from different countries that originated from a single patent application.
World International Property Office (WIPO) PatentScope
Although more limited coverage than EPO's Espacenet, with 37 million documents PatentScope is still useful for its specialized search tools and data. PatentScope is primarily based on Patent Cooperation Treaty (PCT) applications originating from around the world. The PCT allows inventors to file a patent in just one country, but also initiates filing in up to 145 other countries ( The database has some unique search features: the CLIR tool which allows you to enter search terms from multiple languages, searching and browsing by IPC classifications, and limiting results by country of origin. Documents are available as TIFF image files; PDFs are available for most patents. You can also download genome sequence data from PCT applications.
Google Patents
After starting with scanned USPTO documents, Google has expanded their patent search to include international patent organizations. Beyond the easy-to-use search interface, the main benefit of Google Patents is the ability to search full-text of pre-1976 U.S. patents. Google has the most comprehensive database for historic patents. The "Search Tools" and "Advanced Search" interfaces should be used for more effective searching. There is also a "Prior Art Search" that can be used from any patent or application to look for similar keywords in earlier patents and across Google's web search. This search technique is most effective with recent patent documents. Google Patents makes the raw data available to download through an agreement with the USPTO.
The Lens
Formerly known as Patent Lens, the Lens is an online search tool for patents that offers some unique features. After signing up for a free account, you can build collections of patents to create graphical reports and download spreadsheets of bibliographic data from a collection. This is very useful for researchers in patent landscaping, which tracks the number of patents in an industry over a period of time in an attempt to forecast the value of patents or the growth of industry; it is also useful for those seeking all patents from a single company. The search interface itself provides quick graphical summaries of fields, including patent office ("jurisdiction"), publication by year, and patent citations. The most unique features of the Lens are its Patent Sequence Data tools ( Each of the tools can be useful for different types of genomic sequence research – from text searching to sequence searching to exploring related sequences based on species or patent.
FreePatentsOnline (FPO) / SumoBrain
The FreePatentsOnline (FPO) web site is a useful source of PDF patent files and RSS feeds for new patent information. RSS feeds will push updates when new patent documents are published in a specified classification or in one of FPO's technology areas. FPO mainly draws on the USPTO for data, but has also added some international patent offices. SumoBrain is another web site from FPO. It adds more search features, statistical information, and the ability to download data. After signing up for a free account, you can create portfolios from patent search results. The bibliographic data from this can be exported into a spreadsheet, which is useful for those doing company research or needing multiple patent results.
Derwent World Patent Index - Thomson Reuters (subscription)
The Derwent World Patent Index adds additional information to patents such as: uniform assignee information (ex. the many permutations of IBM), enhanced titles and abstracts simplified into layman's terms, and its own proprietary classification system (Derwent class codes and Derwent manual codes). Derwent is available through either the Thompson Innovation platform or Web of Knowledge. Depending on the interface, different functionality is available along with different costs. Thompson Innovation has additional information such as pending litigation, legal status, licenses, and related USPTO announcements. It also allows researchers to perform analyses such as text clustering, patent landscaping, and generating charts. Both Innovation and Web of Knowledge platforms allow export of patents.
SciFinder Scholar - Chemical Abstract Service (CAS) (subscription)
The American Chemical Society (ACS) has been indexing chemical patents through CAS since the early 20th century. Today, CAS has patent information from many international patent offices, often within days of publication (check for current years of coverage While only chemical patents from select classifications are indexed, the information gathered is robust and allows for the patents to be fully integrated into the SciFinder system. Patents can be searched separately by basic fields, such as inventor or patent number, but also can be found in all other search results. Limiting by document type can focus results only on patents. Chemical structure searching is also possible, including a special Markush structure search. Markush structures are used in patents to claim multiple similar chemical structures; these include "prophetic" substances, chemicals claimed in patents that have not been produced in the lab but which are included in CAS and given a Registry Number. For a detailed explanation of searching for chemistry and chemical information in patents, please refer to White 2014.
Reaxys - Elsevier (subscription)
Reaxys from Elsevier, based on the Beilstein and Gmelin databases with added patent data, offers many of the same tools and data as SciFinder Scholar. Though coverage of historic patents was primarily from patents selected for Beilstein and Gmelin beginning in 1920, Reaxys has patent data since 1976 from the major patent granting organizations: the USPTO, the WIPO, and the EPO.
SureChem is a free web site offering similar data and search functions as SciFinder Scholar. It has keyword searching and structure searching of documents from the major patent sources (USPTO, EPO, WIPO, and the Japanese Patent Office). From the search results, it provides a unique tool to highlight all related patents from different countries (the patent family) and to export the chemical information from selected patents. In order to export, first select a patent or family and the data of interest, such as molecular weight and a SMILES (Simplified molecular-input line-entry system) description of the structure; after starting the export, it will run and be available for one day for download from the site.


Baldwin, V. 2008. Patent information in science, technical, and Medical Library instruction. Science and Technology Libraries 28(3): 263-270.

Kawakami, A. 1998. Patents and patent searching. Issues in Science and Technology Librarianship [Online]. Available: [Accessed: November 20, 2014].

LaCourse, P. 2010. Science and technology resources on the Internet: End-user patent searching using open access sources. Issues in Science and Technology Librarianship [Online]. Available: [Accessed: November 20, 2014].

Meier, J. 2012. Patents. In: O'Clair, K., and Davidson, J., editors. The Busy Librarian's Guide to Information Literacy in Science and Engineering. Chicago (IL): Association of College and Research Libraries. p. 93-104.

White, M. 2014. Chemical Patents. In: Currano, J., and Roth, D., editors. Chemical Information for Chemists: A Primer. Cambridge (UK): Royal Society of Chemistry. p. 53-89.

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