Perhaps you should try some spelling variations:
ratings risk » patients risk
direct cost » direct costs, indirect cost, indirect costs
wang liang » wang yang
liang yang » liang ying, wang yang, yang yang
life cost » life costs, life lost, life case
among men » among women
die cost » diet cost, die post, die ost

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

• If you are trying to use Boolean operators, they must be ALL CAPS: wang liang yang ((((die cost) OR (life cost))) OR (direct cost)) ratings risk among men ;~.
• Adding a wildcard symbol may retrieve word variants: wang liang yang ((((die cost) or (life cost))) or (direct cost)) ratings risk among men ;*.