Perhaps you should try some spelling variations:
ratings risk » patients risk
dan yang » daun yang, tan yang, wang yang
der cost » oder cost, user cost, debt cost
can post » can cost, can lost, can postal
can past » can east, can fast, canal past
wan dan » wang dan, wan daud, awam dan
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.

• If you are trying to use Boolean operators, they must be ALL CAPS: wan dan yang ((((der cost) OR (can post))) OR (can past)) ratings risk ((how shu) OR (how she)) ;~.
• Adding a wildcard symbol may retrieve word variants: wan dan yang ((((der cost) or (can post))) or (can past)) ratings risk ((how shu) or (how she)) ;*.