The Cochrane Reviews are one of the most trusted sources of evidence based medicine reviews. The summaries include a plain language summary, and an abstract that includes a brief background statement, objectives, search strategy, data collection and analysis, results, and concluding statement, while the full text gives more detail on the methodology of the reviews and the studies covered by the reviews, as well as a full reference list. Since the search strategy often includes searches in MEDLINE and CINAHL, you can do a similar search to find likely articles.
Cochrane also produces searchable collections of clinical trials and protocols.