Perhaps you should try some spelling variations:
cost patients » cost patient, cleft patients, care patients
patients risk » patient risk, patients links, patients si
liang ying » liang liying, huang ying, zhang ying
yang yang » wang yang, wang yan
hua cost » a cost, eu cost, run cost
hong shu » tong shui, wong shiu, hong seo

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

• Performing a fuzzy search may retrieve terms with similar spellings: wang ((liang ying) or (yang yang)) hua cost patients risk ((hong shu) or (cong shu)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang ((liang ying) OR (yang yang)) hua cost patients risk ((hong shu) OR (cong shu)) ;.
• Adding a wildcard symbol may retrieve word variants: wang ((liang ying) or (yang yang)) hua cost patients risk ((hong shu) or (cong shu)) ;*.