Tip: Try searching for digital copies of primary source material by using the phrase "digital collections" or "digital archive" as part of your search along with keywords that describe your topic.
For example:
September 11 Digital Archive -- The September 11 Digital Archive uses electronic media to collect, preserve, and present the history of September 11, 2001 and its aftermath. The Archive contains more than 150,000 digital items, a tally that includes more than 40,000 emails and other electronic communications, more than 40,000 first-hand stories, and more than 15,000 digital images.
AdViews: A Digital Archive of Vintage Television Commercials -- AdViews is a digital archive of thousands of vintage television commercials dating from the 1950s to the 1980s.
Also, GALILEO
has many digital collections on a variety of topics listed under "Archives and Primary Sources" and "Digital Collections and Repositories". See the complete list of categories under "Browse by Type".