Perhaps you should try some spelling variations:
training visit » training cost, training test
trading case » trading costs, leading cause, trading value
hua credit » dual credit, a credit, ida credit
dong yang » dong hoang, wang yang, yang yang
yang ya » yang yi, yang ka, yang y
cong » congo, long, hong

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

• Performing a fuzzy search may retrieve terms with similar spellings: dong yang ya hua credit ((trading case) or (training visit)) cong shu ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: dong yang ya hua credit ((trading case) OR (training visit)) cong shu ;.
• Adding a wildcard symbol may retrieve word variants: dong yang ya hua credit ((trading case) or (training visit)) cong shu ;*.