Perhaps you should try some spelling variations:
cost ratings » cost savings, costs savings, bond ratings
ratings risk » patients risk
liang yang » liang ying, wang yang, huang yang
yang yang » wang yang, wang yan
risk tong » risk among, risk along
tong shui » tong hui, cong shu, gong hui
hua cost » a 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 ((liang yang) or (yang yang)) hua cost ratings risk tong shui ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang ((liang yang) OR (yang yang)) hua cost ratings risk tong shui ;.
• Adding a wildcard symbol may retrieve word variants: wang ((liang yang) or (yang yang)) hua cost ratings risk tong shui ;*.