Perhaps you should try some spelling variations:
patients risk » patient risk, patients links, patients si
huang yang » huang ying, huang chang, yang yang
wang yang » wang yan, wang liang, wang yanling
among who » along who, among hr, wrong who
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 ((huang yang) OR (wang yang)) ((can lost) OR (can cost)) patients risk among who ;~.
• Adding a wildcard symbol may retrieve word variants: wang ((huang yang) or (wang yang)) ((can lost) or (can cost)) patients risk among who ;*.