Perhaps you should try some spelling variations:
credit trading » credit training, credit rating, credit standing
dual credit » rural credit, deals credit, equal credit
value cong » value closing, value change
yang yang » wang yang, wang yan
value co » value _, value a
a dual » _ dual
dong » doing, long, done

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((dong sin) or (yang yang)) a dual credit trading ((value cong) OR (value co)) shu ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((dong sin) OR (yang yang)) a dual credit trading ((value cong) OR (value co)) shu ;*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((dong sin) or (yang yang)) a dual credit trading ((value cong) OR (value co)) shu ;*".