Perhaps you should try some spelling variations:
patient risk » patients risk, patient task, patient cost
wang wang » wang liang, wang yan, wang yong
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 wang) OR (wang yang)) yanling ((can lost) OR (can cost)) patient risk among who ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((wang wang) OR (wang yang)) yanling ((can lost) or (can cost)) patient risk among who ;~".
• Adding a wildcard symbol may retrieve word variants: ((wang wang) OR (wang yang)) yanling ((can lost) or (can cost)) patient risk among who ;*.