Search PubMed/MEDLINE for biomedical literature via NCBI E-utilities API. Use when: (1) searching medical/biomedical papers, (2) finding clinical studies, (3) querying with MeSH terms, (4) retrieving abstracts by PMID. NOT for: non-biomedical papers (use arxiv-search or semantic-scholar), full-text access (PubMed provides abstracts), or social science literature.
Search PubMed/MEDLINE (36M+ citations) via NCBI E-utilities REST API.
Base: https://eutils.ncbi.nlm.nih.gov/entrez/eutils/
curl -s "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=COVID-19+vaccine+efficacy&retmax=10&retmode=json"
Parameters: db=pubmed, term= (URL-encoded query), retmax= (default 20, max 10000),
retstart= (pagination), retmode=json, sort=relevance|pub_date,
mindate=/maxdate= (YYYY/MM/DD), datetype=pdat.
curl -s "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&id=39142890,39088712&retmode=xml&rettype=abstract"
curl -s "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/einfo.fcgi?db=pubmed&retmode=json"
Boolean: AND, OR, NOT, parentheses for grouping.
Field tags: [ti] title, [tiab] title/abstract, [au] author, [mesh] MeSH heading,
[majr] MeSH major topic, [pt] publication type, [dp] date, [la] language, [jour] journal.
MeSH terms: Standardized vocabulary with automatic explosion to narrower terms.
Use [mesh:noexp] for exact heading only. Qualifiers: /therapy, /diagnosis,
/epidemiology, /genetics, /prevention and control.
Example: "Breast Neoplasms"[mesh] AND "Drug Therapy"[mesh]
NCBI_API_KEY: 10 requests/sec (append &api_key=${NCBI_API_KEY})PMIDS=$(curl -s "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=QUERY&retmax=5&retmode=json" \
| python3 -c "import sys,json; d=json.load(sys.stdin); print(','.join(d['esearchresult']['idlist']))")
curl -s "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pubmed&id=${PMIDS}&retmode=xml&rettype=abstract"
"Neoplasms"[mesh] AND "immunotherapy"[tiab] AND "Clinical Trial"[pt]"Cardiovascular Diseases"[mesh] AND "meta-analysis"[pt]"Alzheimer Disease"[mesh] AND "biomarkers"[tiab] AND 2020:2024[dp]"Anti-Bacterial Agents"[mesh] AND "Drug Resistance"[mesh]"Genome-Wide Association Study"[pt] AND "Diabetes Mellitus, Type 2"[mesh]"systematic review"[ti] AND "Randomized Controlled Trial"[pt]retmax=5 for exploration, increase for comprehensive searches.+, quotes as %22).count in esearch results before paginating."systematic review"[ti] combined with study type filters.NEVER fabricate results from training data. Every paper title, author, DOI, PMID, citation count, and metadata detail presented to the user MUST come from an actual API response in this conversation. If the API returns no results or partial data, report exactly what was returned. Do not "fill in" missing details from memory.