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Open content in WorldCat Discovery search results

Learn about Open Access in WorldCat Discovery.

Open Access filter

The Open Access content filter narrows a user's search over the WorldCat database. Open Access results can be filtered on the Advanced Search screen and in search filters using Filter and refine search results

The Open Access filter searches for records cataloged with the recent Open Access for URLs MARC standard. The Open Access filter uses the op: 0 index. Users can also manually enter op: 0 into the search bar to return these records.

See 856 Electronic Location and Access, ǂ7 Access status for more information.

The Open Access filter returns records from WorldCat that contain either:

  • An 856 field with:
    • First indicator 4 and second indicator 0
    • A subfield 7 that is equal to 0


  • A 506 field with
    • Subfield a of Unrestricted Access Online

The Open Access subset of databases from include:

  • BioMed Central
  • Directory of Open Access Books (DOAB)
  • Directory of Open Access Journals (DOAJ)
  • Europeana
  • HBO Kennisbank
  • Hindawi eJournals
  • JSTOR Open Access Books
  • JSTOR Open Access Journal Collection
  • JSTOR Open Community Collections
  • JSTOR Reveal Digital American Prison Newspapers
  • JSTOR Reveal Digital Independent Voices
  • Knowledge Unlatched
  • OAIster
  • Open Access Publishing in European Networks (OAPEN)
  • Open Library of Humanities
  • OpenEdition Books
  • OpenEdition Hypotheses
  • OpenEdition
  • Paperity
  • Public Library of Science (PLOS)
  • Project Euclid
  • SciELO Journals
  • UCL Press Journals
  • Wolters Kluwer Medknow

Open Access DOI links enhanced by Unpaywall

Users can access open content using DOI full text and open access links provided by Unpaywall. For more information see, When enabled, DOIs will inform the Access Online action on search results, detailed records, and Course Reserves. DOIs are compared to Unpaywall data to ensure that only DOIs leading to open access content display. When a DOI leads to a downloadable PDF, a View PDF button appears on DOI links enhanced by Unpaywall. When it cannot be determined that a DOI link informed by Unpaywall leads to a PDF, a link to Access Online <insert DOI> appears. If a DOI is not present in Unpaywall, the DOI will not inform the Access Online button, but will continue to display in the Description of detailed records.

 Note: If a user encounters a link from Unpaywall that does not lead to Open Access, you will need to contact Unpaywall directly to have the link corrected. Please see, Tips to identify elink sources in WorldCat Discovery to determine if the link in question is a DOI link.

Configure Open Access links

Open Access configuration is managed in OCLC Service Configuration. For more information, see Full Text and Open Access Links.