Below, are some primary source databases that are available freely online or through UNCW Library. These only scratch the surface of online collections of primary sources. To search more specifically for your topic, try searching for the topic plus archives, primary sources, or digital collection. For example, doing a quick search for civil rights primary sources in Google finds this Civil Rights Digital Library, containing important documents, photographs, and videos from the Civil Rights era.
PLEASE NOTE: All UNCW Library primary source databases are listed here (or, from the library homepage, go to Databases --> By Type --> Primary Sources (Historical)). They cover both U.S. and international topics, stretching back centuries.