Perhaps you should try some spelling variations:
training cost » training costs, training course, training courses
trading case » trading costs, trade case
trading cost » trading costs
dual credit » rural credit, deals credit, equal credit
dong nan » dong yang, dong sin, dong bin
hong shu » cong shu, tong shui, wong shiu
ya dual » a dual, via dual
nan ya » nan yan, nana yaa

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 nan ya dual credit ((trading case) OR (((trading cost) OR (training cost)))) hong shu ;~.
• Adding a wildcard symbol may retrieve word variants: dong nan ya dual credit ((trading case) or (((trading cost) or (training cost)))) hong shu ;*.