First, understand that finding articles and using them as evidence for your point, topic, etc. is a part of Evidence-Based Practice, which is the standard for your profession. "Evidence based practice (EBP) is the conscientious use of current best evidence in making decisions about patient care." --Sackett, Straus, Richardson, Rosenberg, & Haynes, 2000.
Looking to the literature to supply statistics, examples, and theory to why you are answering your question or supporting your topic in such a way demonstrates your credibility. If you are not credible, then why should a patient believe you? Why should a colleague work with you? What if you didn't use literature to back up your decision and you discovered that you made a medical error?
PubMed - One of the best places to search for medical/health-related research studies. Nice features of PubMed include:
SportDiscus - Focuses on sport-related research, a smaller place than PubMed, but also excellent.
TRIP - Searches medical/health research as well as best practices and guidelines. Nice features of TRIP include:
If a research article, then: