Perhaps you should try some spelling variations:
ratings risk » patients risk
wang yang » wang yan, wang liang, wang yanling
wan wang » wen wang, yan wang, qian wang
der cost » oder cost, user cost, debt cost
can cost » can costa, can lost, can post
can east » can fast, can past, plan east
how shih » how six
how she » how some, how safe

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

• Performing a fuzzy search may retrieve terms with similar spellings: wan wang yang ((((der cost) or (can cost))) or (can east)) ratings risk ((how shih) or (how she)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wan wang yang ((((der cost) OR (can cost))) OR (can east)) ratings risk ((how shih) OR (how she)) ;.
• Adding a wildcard symbol may retrieve word variants: wan wang yang ((((der cost) or (can cost))) or (can east)) ratings risk ((how shih) or (how she)) ;*.