PubMed Central (PMC): free digital archive of biomedical literature

Key characteristics

PMC is distinguished by several operational features:

• Open full-text access: articles in the archive are available to read at no charge.
• Publisher and author deposits: content arrives through journal participation, direct author submissions, and funding-mandated deposits.
• Embargo policies: some publishers permit delay of public release for a limited period after publication; embargo lengths vary by journal.
• Searchable XML: articles are stored in structured formats to support text mining and advanced searching.

History and development

PMC launched in 2000 as an effort to preserve and provide access to the scholarly literature in the biomedical sciences. It was created by the NLM and expanded from earlier online services and databases. Over time the repository attracted participation from many journals and research funders; by the early 2020s it contained millions of articles and continued to grow as open access and public‑access policies became more common.

Uses and significance

Researchers, clinicians, students and the public use PMC to obtain reliable primary literature without paywalls. It supports systematic reviews, teaching, clinical decision making and computational research that requires large collections of full text. Funders and institutions often reference PMC and related pages for compliance and reporting; see institutional guidance and policy pages such as those provided by funding agencies for details.

Access model, policies and practical notes

Access to content depends on agreements between publishers and the archive and on funder mandates. For example, authors who receive certain government funding may be required to deposit a copy of their accepted manuscript into PMC within a set time frame. Many journals participate voluntarily and some apply short embargo periods. For technical and usage information, the NLM hosts documentation and user guides available from its home and help pages, including the NLM portal at NLM and other resource pages at PMC-related resources.

PMC remains an important public resource for preserving the scholarly record, increasing accessibility of research, and enabling data-driven studies that rely on open, machine-readable full text.