Databases primarily index articles--they tells you what has been written. Some provide full-text access, but many will require an interlibrary loan request.
Start with these when looking for exercise science related article.
This interdisciplinary database provides full text access to over 8,500 academic journals in the social sciences, humanities, general science, education, and multi-cultural journals.
Indexes 31+ million references to biomedical and life science journal articles. It often links to the full-text of an article, and a majority of the journals are fairly technical.
Google Scholar provides a simple way to broadly search for scholarly literature in one place across many disciplines and sources: articles, theses, books, etc.
