Database Search Tips
Many databases allow you to limit your search to peer-reviewed articles.
To find out if a journal is peer reviewed (i.e. evaluated by other scholars working in the same field), consult Ulrich's Periodicals Directory, Journal Guide or QOAM (Quality Open Access Market).
See also: Journal Metrics and How to Assess a Journal [PDF]
Keeping Up-to-date with Research
To search for an open access version of any article, try DOAI.IO or Unpaywall.