The Library of Congress defines primary sources as the "raw materials of history—original documents and objects created at the time under study. They are different from secondary sources, accounts or interpretations of events created by someone without firsthand experience."
A secondary source used differently can become a primary source. For example, for a nineteenth century health professional, articles published in scholarly medical journals were secondary sources, synthesizing observations of patients into recommendations for care. But for today's historian of medicine, those same journal articles can be used as primary source evidence for historical attitudes and practices.
Even though you can browse these journals online, you won't necessarily be able to see the full text. But don't worry! We'll show you how you can request materials through Interlibrary Loan. Articles usually arrive 1–3 days after you submit the request, and you'll receive an email notifying you that the article PDF is available for you to download.