This classic reference source features thousands of entries on a wide range of topics in American history, from precolonial days to 2003. This is a useful resource for anybody studying for the AP US History exam as well as for writing any US history research papers.
The Encyclopedia Britannica is the oldest English-language encyclopedia and boasts more than 40,000 articles on a variety of subjects. This website also includes videos, images, biographies, and links to websites, and is a great resource to begin research.
This encyclopedia contains more than 750 articles that explore major topics related to global warming and climate change. It is international in scope, and covers a broad range of topics such as alternative energy, carbon cycle, climate models, effects of climate change, institutions & people studying climate change, paleoclimates, and sea level rise. This can be valuable to anybody interested in global warming or for those studying the subject in an Environmental Science class.
This resource has over 2,500 entries that cover all major areas of science, including biology, genetics, microbiology, astronomy, geology, chemistry, physics, technology, and mathematics.
Grizmek’s Animal Life Encyclopedia has been a resource for the animal science community since 1960. With frequent updates to incorporate the most recent developments in the animal world, this is a great tool for anyone doing research on the natural world.
The OED is the most-trusted, authoritative guide to definitions, etymology, and pronunciation of words in the English language. It not only provides modern definitions of words, but also their historic meanings and their first recorded usages.