Academic article databases are often broken up by discipline. It helps if you know in advance what academic literature you want to search: political science, economics, psychology, education, sociology, health, science, et al. Here are links to the essential databases that will help you find articles in those fields, as well as links to research guides that provide more detail in those areas. Check out Virgo, UVA Library's catalog, for books.
Additionally, the following databases are good for any science or social science article search.