Perhaps you should try some spelling variations:
patients risk » patient risk, patients links, patients si
cost patients » cost patient, cleft patients, care patients
tong shui » tong hui, cong shu
gong hui » tong hui, wang hui, gong si
yang up » yang jui, tying up, yang jun
yang xi » yang di, yang yi, yang jui

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: (wan OR wing) yanling ((yang up) OR (yang xi)) cost patients risk ((tong shui) OR (gong hui)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(wan or wing) yanling ((yang up) or (yang xi)) cost patients risk ((tong shui) OR (gong hui)) ;~".
• Adding a wildcard symbol may retrieve word variants: (wan or wing) yanling ((yang up) or (yang xi)) cost patients risk ((tong shui) OR (gong hui)) ;*.