ProQuest allows you to search multiple databases with a single search. Here are links to search screens for some common combinations of their newspaper databases.
The UCLA Library has many newspapers in its collections that have not been digitized. They are not easily searchable in the UCLA Library Catalog if you do not know the title of the newspaper. If you are looking for newspapers from a specific city, you can search WorldCat and limit to newspapers in the UCLA Library. The search strategy to use is:
The results will be a list of newspapers from the publisher location searched.
Selected Southern California newspapers are listed below:
http://archive.org - online versions of microfilm reels; search term: UCLA Daily Bruin. Keyword searching is available within each reel
The Daily Bruin went online in Fall Quarter, 1994: http://dailybruin.com/