When searching for primary sources, include the types of primary sources (e.g. pamphlets, speeches) you are looking for in your search.
For example: if you are looking for personal memoirs on slavery, your search words could be slave AND diary.
For a full list of primary source types to include in your search, refer to the homepage of this guide.
Academic Search Complete allows you to limit your search to Primary Source Documents, under Publication Type, before running your search.
When visiting other databases, you should check for similar filters.