Searches PubMed for biomedical literature by free-text query, with optional date range and sort (relevance / pub_date / first_author). Returns total hit count plus PMID, title, authors, journal, publication date, abstract, MeSH terms, and DOI per paper. Federal public-domain data via NCBI. Use it as a medical journal lookup, NIH paper search, clinical-research finder, MeSH-term query, or NCBI E-utilities wrapper.