America History & Life is the best database to use when looking for academic journal articles in the field of African American history.
Link your search terms using the AND connector. For example: blacks and labor unions and discrimination. On the search results screen, use the options on the left toolbar to narrow your search results. To find the fulltext of the article (if not provided directly in the database), click on the "Check for Full Text" button and work your way through the screens. Not all articles will be online, some may only be in print, others may not be available at the UW. Articles from journals which the UW does not own can be requested via Interlibrary loan.
Keep in mind that when searching for articles dealing with African Americans that America History & Life mostly uses the term "Blacks" but will also "African Americans" so you will want to search using both terms.