Some magazines are digitized in Google Books, lncluding Life Magazine (digitized and keyword searchable from 1935-1972, no printing.) Use the link to browse a list of other titles available. Or, do an advanced search of Google books, limiting to magazines, notice you can also select a date range. Mostly articles from U.S. during 20th century
Back issues of the New York Times newspaper, published since 1851 are searchable from the newspaper's website. All site license users (Armstrong students, faculty and staff) have unlimited searching back to 1851-current. They are limited to 5 PDF downloads per day for the period of 1923-1980, due to copyright restrictions. Otherwise, there is no limit on downloads.
Here's a sample search, started with keywords, savannah slavery and limited by date: 01/01/1851-01/01/1900:
If you are not an Arrmstrong student/faculty/staff, a digital subscription to the New York Times (academic rate is currently $5 for first 12 weeks) means access all the back issues and current articles.
Lane Library's Special Collections houses The Inkwell, Armstrong's student newspaper from the first issue (September 1935) through current issues. See below for links to the digitized back issues from 1935-1947, 1955, & 1960-1971 and the current, online issues.
JStor includes historical sources.. For example currently in JStor American Naturalist is available from 1867-2015, American Scholar runs 1932-2011 and American Sociologist 1965-2013. Some JStor journals date to the 19th century, many started in the early 20th.