Perhaps you should try some spelling variations:
rating costs » trading costs, roaming costs, rising costs
risk rating » risk taking, risk sharing
wan yanling » wang yanling, wang yangming, wang danning
dong skin » dong sin, dong bin, dof skin
how shih » how she
how six » how asia
a a » a la

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 yanling) OR (dong skin)) a a risk rating costs ((how shih) OR (how six)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((wan yanling) or (dong skin)) a a risk rating costs ((how shih) OR (how six)) ;~".
• Adding a wildcard symbol may retrieve word variants: ((wan yanling) or (dong skin)) a a risk rating costs ((how shih) OR (how six)) ;*.