The Libraries have a LOT of e-journal subscriptions and hundreds of databases designed to help you find them. You can use PRIMO, the main catalog, to find interesting secondary sources (like articles!). For specialized US history topics, you may want to try America: History and Life. Both work in a similar manner.
Lets' say my topic is women's education in Virginia , so I try the search:
Women AND education AND Virginia
In these databases, start with basic keyword searches. If you get too many results, try different keywords or narrow your search to "title" or "Abstract" searches.
Example: A keyword search for schoolhouse* or "School house*" in America: History and Life brings up 338 results, but the same search limited to Title brings up only 136