The State Historical Society of Missouri has digitised the archives of the Missouri Historical Review and made it freely available online.
From their announcement:
This award-winning scholarly journal is published quarterly and has been the cornerstone of the Society’s publication division for over one hundred years. Richly illustrated and featuring contemporary scholarship on all facets of state and regional history, the journal also contains reviews of recently published books and offers notes and short pieces on local culture and Missouri life. Users will find within each issue a wealth of information on significant events and persons in Missouri history as authors have explored the political culture of antebellum days, Civil War battles and politics, religious and ethnic heritage in the state, and a wide variety of other topics.
Researchers can search the online Missouri Historical Review by keyword or browse through pages for more general findings. Volumes are added to the online database once they are ten years old.
You can access the archives at: http://statehistoricalsocietyofmissouri.org/collections/mhr.php