Perhaps you should try some spelling variations:
patients risk » patient risk, patients links, patients si
huang yang » huang ying, huang chang, wang yang
yang yang » wang yang, wang yan
risk wong » risk among, risk along, risk work
wong shiu » wong siu, cong shu, song shin
hua cost » eu cost, run cost

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

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