Perhaps you should try some spelling variations:
ratings risk » patients risk
among users » among ers, among peers, among masters
wang liang » wang yang
liang yang » liang ying, wang yang, yang yang
can close » can lose, a close, can cause
can lost » can lose, can post, can boost
can cost » can costa, can post, chain cost

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: wang liang yang ((((can lost) OR (can close))) OR (can cost)) ratings risk among users ;~.
• Adding a wildcard symbol may retrieve word variants: wang liang yang ((((can lost) or (can close))) or (can cost)) ratings risk among users ;*.