Perhaps you should try some spelling variations:
costs ratings » costs savings, costs creating, cost savings
ratings risk » patients risk
liang ying » liang liying, huang ying, zhang ying
risk wrong » risk among, risk along
yang yang » wang yang, wang yan
wrong who » wrong why, wrong what, wrong when

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

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