Entrez is NCBI’s primary text search and retrieval system that integrates the PubMed database of biomedical literature with 39 other literature and molecular databases including DNA and protein sequence, structure, gene, genome, genetic variation and gene expression.

Links to Genbank database, tools for data mining including BLAST, COGS, MapViewer, LocusLink, UniGen, ORF finder, Electronic PCR, VAST search, CCAP, Human-Mouse Homology maps, VecScreen, and Cancer Genome Anatomy Project. Also provides access to Entrez: a retrieval system for searching several linked databases, including PubMed, Nucleotide sequence database, protein sequence database, structure, genome, population data sets, Online Mendelian Inheritance in Man, taxonomy, 3D domains, ProbeSet, and online books.