The databases below allow you to search through a LOT of different periodicals (journals, magazines, newspapers, etc.) at once. Some of them are very broad and include periodicals from a variety of different academic disciplines (for example, ProQuest Research Library and JSTOR). Others are more subject-focused, and include only journals or periodicals related to a specific discipline (for example, Communication and Mass Media Complete). Always keep in mind what kinds of resources are included, in whichever database you choose.
Not sure where to start? These online databases allow you to search through thousands of articles, from many different newspapers, at the same time.