Perhaps you should try some spelling variations:
patients risk » patient risk, patients links, patients si
cost patients » cost patient, cleft patients, care patients
wan yanling » wang yanling, wang yangming, wang danning
yang jun » yang jui, pang jun, yang jin
ying jin » yang jin, jing ji, yang jie
among eu » among men, among _, among 15

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 yanling ((yang jun) OR (ying jin)) cost patients risk among eu ;~.
• Adding a wildcard symbol may retrieve word variants: wan yanling ((yang jun) or (ying jin)) cost patients risk among eu ;*.