eLS (Encyclopedia of Life Sciences) : Citable reviews in the life sciencesThis is a good place to learn about biology topics that are new to you, or to get an overview of a multidisciplinary subject.
This is a major comprehensive encyclopedia including biology, ecology, environmental and health sciences, genetics & molecular biology, immunology, microbiology, virology, and biochemistry.
The articles are peer-reviewed and regularly updated. The encyclopedia may be browsed by article title, subject or contributing author, or searched by keywords.