Newspaper databases tend to include only articles written by journalists, and op-ed pieces written by invitation. The databases will not include advertisements, classifieds, or uninvited letters to the editor.
Academic Search Ultimate, ProQuest Research Library, and the OneSearch search box all allow you to limit your search to News or Newspapers, but those database are mostly for artices, and do not have large holdings of newspapers.
On the Popular Databases page, there is a box for the NEWSPAPER databases. Newsbank is by far the largest database. This is an international database, and has historical holdings of many local and regional US newspapers, even papers that have ceased publication.
As KU students, you can register for free subscriptions to the New York Times, the Washington Post, and the Wall Street Journal.
The latest information on signing-up for an account is HERE
