Google–not to mention yahoo, bing & other web search engines–are mere popularity contests of literature. Google Scholar is a step up, but it is still a search engine. It can miss important articles entirely.
If you want to be sure that you are getting the BEST, you gotta look in the right place if you want to find the right articles on the right topic at the right time!
You need a Database!
Don’t believe me? Watch “What are databases and why you need them?”(youtube 2:34)
Reputable publishers give away very few articles for free, so when you want the best literature out there you need a Database that will systematically help you to find quality articles that fit your topic.
PubMed.gov is a tax funded database that is highly comprehensive. CINAHL is strong on nursing literature. If you are enrolled in a university, you have access to lots of full-text articles at no added cost. Check with your librarian if your database search is not turning up what you need–with a few hints, you could get the best.
For more info: Look for that needle in the haystack.