Perhaps you should try some spelling variations:
cost learning » clt learning, ct learning, past learning
learning risk » learning crisis, learning r, learning rate
wang liang » wang yang
risk wrong » risk among, risk along
yang yang » wang yang
wrong who » wrong why, wrong what, wrong when
yang can » yang fan, yang dean, yang jin

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((wang liang) or (wang yan)) ((yang can) OR (yang yang)) cost learning risk wrong who ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((wang liang) OR (wang yan)) ((yang can) OR (yang yang)) cost learning risk wrong who ;*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((wang liang) or (wang yan)) ((yang can) OR (yang yang)) cost learning risk wrong who ;*".