This database for biology and botany citations and abstracts goes back to 1926. Indexes and abstracts from articles in core biological journals worldwide. Complementary to Google Scholar for biology literature searching.
The U.S. database of nucleotide sequences. From their website and Nucleic Acids Research 2005 Jan. 1, 33 (Database issue):D34-D36, it is the NIH genetic sequence database, an annotated collection of all publically available DNA sequences.
Interdisciplinary bibliographic database for all fields in science. (Science Citation Index) Coverage 1900-. Indexes major international journals. Offers cited reference searching in addition to topic and author searching.