Perhaps you should try some spelling variations:
ratings risk » patients risk
yan yang » yang yang, yao yang, dan yang
der cost » oder cost, user cost, debt cost
can lost » can cost, can lose, can post
can past » can east, can fast, can post
wai yan » wang yan, wei yang
how shu » how shih, how slum
how she » how some, how safe, how shih

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

• Performing a fuzzy search may retrieve terms with similar spellings: wai yan yang ((((der cost) OR (can lost))) OR (can past)) ratings risk ((how shu) OR (how she)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wai yan yang ((((der cost) OR (can lost))) OR (can past)) ratings risk ((how shu) OR (how she)) ;".
• Adding a wildcard symbol may retrieve word variants: wai yan yang ((((der cost) OR (can lost))) OR (can past)) ratings risk ((how shu) OR (how she)) ;*.