For onine articles published pre-1928 Magazine Finder provides online access to your article via either an archive or a database.
For print articles (mostly published after 1927) Magazine Finder provides the call number to the volumes of the magazine found in the library basement (first floor of Rod Library). Specific instructions are available for finding magazine articles from various time periods: 1802-1890, 1890-1927, 1928-1982, and 1982-present.
(Note, Time, Life, Fortune and National Geographic have their own searchable archives below).
Though the links above and below go to the Chicago quick guide - the full print Chicago Manual of Style is available for more complicated questions. These large print volumes can be found both at the Library Services Desk and in the Stacks.