In addition to maintaining the GenBank nucleic acid sequence database, the 
National Center for Biotechnology Information (NCBI) provides analysis and 
retrieval resources for the data in GenBank and other biological data made 
available through the NCBI web site. NCBI resources include Entrez, the Entrez 
Programming Utilities, MyNCBI, PubMed, PubMed Central, Entrez Gene, the NCBI 
Taxonomy Browser, BLAST, BLAST Link (BLink), Electronic PCR, OrfFinder, Spidey, 
Splign, RefSeq, UniGene, HomoloGene, ProtEST, dbMHC, dbSNP, Cancer Chromosomes, 
Entrez Genomes and related tools, the Map Viewer, Model Maker, Evidence Viewer, 
Clusters of Orthologous Groups (COGs), Retroviral Genotyping Tools, HIV-1/Human 
Protein Interaction Database, Gene Expression Omnibus (GEO), Entrez Probe, 
GENSAT, Online Mendelian Inheritance in Man (OMIM), Online Mendelian Inheritance 
in Animals (OMIA), the Molecular Modeling Database (MMDB), the Conserved Domain 
Database (CDD), the Conserved Domain Architecture Retrieval Tool (CDART) and the 
PubChem suite of small molecule databases. Augmenting many of the web 
applications is custom implementation of the BLAST program optimized to search 
specialized data sets. All of the resources can be accessed through the NCBI 
home page at www.ncbi.nlm.nih.gov.