PMC (PubMed Central)

PMC is a full-text archive of biomedical and life sciences articles. It is separate from PubMed -- PubMed has citations/abstracts, PMC has full text. Not all PubMed articles are in PMC, and vice versa.

E-utilities for PMC

Base URL

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/

Same E-utilities as PubMed, but with db=pmc.

eSearch -- Search PMC

GET /esearch.fcgi?db=pmc&term={query}&retmode=json

Same parameters as PubMed eSearch. Returns PMC UIDs (numeric, e.g., 13033346). You need to prepend "PMC" to get a PMCID (e.g., PMC13033346).

eFetch -- Get Full Text XML

GET /efetch.fcgi?db=pmc&id={pmcid}&retmode=xml

rettype	retmode	Returns
(omit)	`xml`	Full text JATS XML (body, figures, references)
`medline`	`text`	MEDLINE format

Example:

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pmc&id=7029759&retmode=xml

The XML uses JATS (Journal Article Tag Suite) format:

<front> -- journal metadata, article metadata, author info
<body> -- full article text with <sec> sections, <p> paragraphs, <fig> figures
<back> -- <ref-list> with all references

Pass numeric IDs only (not "PMC7029759", just "7029759").

BioC API -- Structured Full Text

An alternative way to get full text in a structured passage format.

Base URL

https://www.ncbi.nlm.nih.gov/research/bionlp/RESTful/pmcoa.cgi/

Endpoint

GET /BioC_{format}/{id}/{encoding}

Parameter	Values
`format`	`json` or `xml`
`id`	PMID (e.g., `17299597`) or PMCID (e.g., `PMC7029759`)
`encoding`	`unicode` or `ascii`

Example:

https://www.ncbi.nlm.nih.gov/research/bionlp/RESTful/pmcoa.cgi/BioC_json/PMC7029759/unicode

Response structure (JSON):

json

{
  "source": "PMC",
  "documents": [{
    "id": "PMC7029759",
    "infons": {"license": "...", "doi": "..."},
    "passages": [
      {
        "offset": 0,
        "infons": {"section_type": "TITLE"},
        "text": "Article title..."
      },
      {
        "offset": 42,
        "infons": {"section_type": "ABSTRACT"},
        "text": "Abstract text..."
      },
      {
        "offset": 500,
        "infons": {"section_type": "INTRO"},
        "text": "Introduction text..."
      }
    ]
  }]
}

Section types: TITLE, ABSTRACT, INTRO, METHODS, RESULTS, DISCUSS, CONCL, REF, SUPPL, FIG, TABLE

Coverage: ~3 million articles from the PMC Open Access Subset.

PMC ID Converter API

Converts between PMID, PMCID, DOI, and Manuscript ID.

Base URL

https://pmc.ncbi.nlm.nih.gov/tools/idconv/api/v1/articles/

Parameters

Parameter	Required	Description
`ids`	Yes	Up to 200 comma-separated IDs
`idtype`	No	`pmcid`, `pmid`, `mid`, `doi` (default: auto-detect)
`format`	No	`json`, `xml`, `csv` (default: xml)
`tool`	Recommended	Your application name
`email`	Recommended	Your contact email

Example:

https://pmc.ncbi.nlm.nih.gov/tools/idconv/api/v1/articles/?ids=PMC7029759&format=json

Response:

json

{
  "status": "ok",
  "records": [{
    "pmcid": "PMC7029759",
    "pmid": "32117569",
    "doi": "10.12688/f1000research.22211.2"
  }]
}

Only returns results for articles that are in PMC. If an article is in PubMed but not PMC, no PMCID will be returned.

Rate Limits

Service	Limit
E-utilities (`db=pmc`)	3/sec without key, 10/sec with key
BioC API	Follow general NCBI policy (3/sec without key)
ID Converter	Follow general NCBI policy

Include tool and email parameters on E-utility requests. Large batch jobs should run outside peak hours (Mon-Fri 5AM-9PM ET).