Encyclopedias, dictionaries and other reference sources are a great way to get started and to find background information on your topic from various perspectives.
If you want to search for a specific topic or concept across various disciplines to get different perspectives try the following online collection of reference books. For example, do a search on RACE and you will get articles on "race" from reference sources in anthropology, psychology, sociology, biology, etc. Each of the databases below allow you to filter your results by subject.