Books. Use "Library Catalogs" in Scholar OneSearch to find books. Search by a keyword AND a term limiting your results to a type of primary source. For example, Roosevelt and Correspondence or Civil Rights and Interviews.
Journal Databases. A number of journal article databases allow one to search for journal articles on a topic and limit the results to primary sources. One database which has this feature is Academic Search Premier.
Other journal databases allow limiting a search to particular types of primary sources. For example, in MEDLINE one can limit a search to primary source articles on “clinical trials.”
Primary Source Databases. The library also has numerous speciality databases comprised mostly of primary source materials.