Perhaps you should try some spelling variations:
trading volume » trade volume
credit trading » credit training, credit rating, credit standing
dual credit » rural credit, deals credit, equal credit
volume cong » volume one, volume zone, volume change
wang yang » wang liang, wang yanling
a dual » _ dual
dong » doing, long, done

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: ((dong sin) OR (((wang yan) OR (wang yang)))) a dual credit trading volume cong shu ;~.
• Adding a wildcard symbol may retrieve word variants: ((dong sin) or (((wang yan) or (wang yang)))) a dual credit trading volume cong shu ;*.