For national & international news:
U.S. Major Dailies (Chicago Tribune, Los Angeles Times, New York Times, Wall Street Journal, and Washington Post)Contains comprehensive full text for major newspapers from the U.S. and around the world.
For a local or regional news:
Expert researchers use a number of strategies to tweak their searches. Some ideas for re-working searches with disappointing results (too few, too many, not what you expected) are covered in the video below: