UC Berkeley Library subscribes to several databases that include primary sources. You will find them on our A-Z Database List.
Select the Database Type - Archival Collections and Primary Sources.
For other digital collections, check out the links to online primary sources in our many other guides.
Use the search term "primary sources."
Use terminology of the time or country when doing full-text searches, especially within newspaper databases.
Are you working on a Digital Humanities project? Have you tried Gale's Digital Scholar Lab? This cloud-based tool includes several text-mining tools that you can use to analyze many of Gale's digitized primary sources that UC Berkeley holds.