A list of the Marx Library databases relevant to history can be found here: History Databases. You can simply scroll through the tags on the left and select "History" to limit the long list to history resources. These databases may include primary resources like newspapers or secondary sources about certain historical periods or regions.
For general article searches, you might try OneSearch, using the subject terms listed under the "Finding Books" tab in this LibGuide. For articles, though, you might, instead of limiting to books, limit to "Scholarly (Peer Reviewed) Journals"
There are a few ways to find primary sources.
1) Conduct a OneSearch search. Scroll down to the "Source Types" limiter in the left-hand column, click "Show More," and see if "Primary Source Documents" is an option.
If so, you can check the box to the left of "Primary Source Documents" and those primary sources should appear as the search results. (In the above sample search, there would be 3 such sources.)
2) Also in One Search or SOUTHcat Catalog (New), you can use general subject headings or terms to search for primary sources. For example, conducting an advanced search and including "sources" as a subject search in one field, will often yield primary sources among the results.
Also, if you think of what kinds of primary sources might be most relevant to your research, you might include the names of those source types in your advanced search. For example, if examining personal letters would be helpful to your research, you might add "correspondence" to your search.
3) Another useful strategy is to conduct a Google Advanced search and limit your results to .edu or .gov domains. This approach can help you discover useful online repositories of primary sources. The embedded video below explains how to do a Google Advanced search if you haven't used it before.