For more reliable Google results, you can limit your search to a particular site or domain.
e.g. to find Wikipedia articles on sickle cell disease, type "sickle cell" site:en.wikipedia.org
Sites from U.S. institutions of higher education and the U.S. government tend to be more reliable than .coms and even many .orgs.
e.g. "sickle cell" malaria site:.edu
e.g. "sickle cell" malaria site:.gov
Example Using Advanced Search
Review articles in the sciences summarize previously reported findings rather than resent new findings, often pulling together the findings of multiple primary research articles. In doing so, review literature often gives a broader view of the current state of understanding in a given topic area.
Finding review articles is easiest in PubMed. From the Results screen, simply choose "Review" under "Article Type" on the left-hand side.
Unless the database has an easy "Review" limit like PubMed, there is no perfect way to find review articles.
There is no perfect way to find primary research articles.