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 cong » risk coping, risk among, risk along
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 cong shu ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wang ((liang yang) OR (yang yang)) hua cost ratings risk cong shu ;".
• Adding a wildcard symbol may retrieve word variants: wang ((liang yang) OR (yang yang)) hua cost ratings risk cong shu ;*.