Chronicling America: America's Historical Newspapers http://chroniclingamerica.loc.gov/
Great Web Tools for Searching Historical Newspapers https://familysearch.org/blog/en/great-web-tools-searching-historic-newspapers/
How to Find Old Newspaper Articles Online http://www.labnol.org/internet/old-newspaper-articles/18689/
There are many databases that will provide information for historical researchers. America: History and Life and Historical Abstracts includes articles, book reviews, and dissertations on all periods American history published since 1964. It does not always provide access to full-text of items cited, but informs researchers on what has been published and in some cases it provides links to the full text of the articles online. JSTOR, which offers full-text access to over a hundred years of older journals and Project Muse which covers the last five years of scholarly periodicals in many areas including History. Other general databases such as Academic Search Complete and Academic One File provide access to a broad variety of journals and magazine source, or go to a list of databases related to history research, linked above.