The National Center for Biotechnology Information (NCBI) provides analysis and retrieval resources that include the GeneBank, Entrez, MyNCBI, PubMed, Entrez Gene, BLAST, BLAST Link (BLink), Electronic PCR, UniGene, HomoloGene, ProtEST, Cancer Chromosomes, Entrez Genomes, among many others.
PubMed includes over 26 million citations for biomedical literature from MEDLINE, life science journals, and online books. PubMed citations and abstracts include the fields of biomedicine and health, covering portions of the life sciences, behavioral sciences, chemical sciences, and bioengineering. Select full-text is available via PubMed Central.
There are many free bioinformatics data sources on the Internet. Many of them are "mirror sites," which are duplicated sites. Mirror sites help direct traffic from overloading one site and help preserve the data by making multiple copies of it.
Finding sequences of DNA, RNA, or proteins.