Shorten keywords and use a * symbol to get more relevant results:
you'll get results including concussion, concussions, concuss and concussed
There are over 100,000 concussion research articles available via CMCC Library.
A good place to begin is CMCC Discovery Search.
Clinical Databases such as MedLine, CINAHL and SportDiscus are also good choices. Each of these incude many concussion-related full-text articles.
Systematic Reviews can be found in many CMCC resources, especially Cochrane Library and MedLine.