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Accessing UMLS® Knowledge Sources

The UMLS Knowledge Sources are available free of charge to U.S. and international users. Access to the UMLS Metathesaurus requires a license agreement.

bullet  Metathesaurus
To access or download UMLS Metathesaurus data, go to the Web site below and electronically sign a copy of the license agreement. We will send you an e-mail verification to which you must respond within 72 hours to complete the license process. You will then be sent a license number and instructions for accessing or downloading the Metathesaurus.

     License Agreement for Use of the UMLS Metathesaurus - indicates additional restrictions and licensing, if any, that apply for use of vocabularies obtained through the Metathesaurus.


bullet  Semantic Network, SPECIALIST Lexicon, and Lexical Programs
The Semantic Network, SPECIALIST lexicon, and lexical tools are available under "open" terms, which include appropriate acknowledgement for their use.

     Semantic Network (terms and conditions of use)
     SPECIALIST Lexicon and Lexical Programs (terms and conditions of use)


bullet  UMLS Knowledge Source Server (UMLSKS)
The UMLSKS is a set of web based interactive tools and a programmer interface to the UMLS Knowledge Sources and related lexical tools. In addition to searching, the UMLSKS is the source for downloading UMLS Knowledge Sources and programs.

     UMLS Knowledge Source Server


bullet  DVD
The Metathesaurus, the Semantic Network, and the SPECIALIST Lexicon are available in UTF-8 format on DVD-ROM by request.

      Request DVD - include your new license number in the message
      Using the DVD

Last reviewed: 02 November 2007
Last updated: 02 November 2007
First published: 19 March 2004
Metadata| Permanence level: Permanence Not Guaranteed