Perhaps you should try some spelling variations:
training cost » training costs, training course, training courses
trading cost » trading costs, trading case
hua credit » dual credit, a credit, du credit
coping shu » cong shu
yang yang » wang yang, wang yan
yang yala » yang yao, yang all, yang dali

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

• Performing a fuzzy search may retrieve terms with similar spellings: yang yang yala ((hua credit) or (ida credits)) ((trading cost) OR (training cost)) coping shu ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: yang yang yala ((hua credit) OR (ida credits)) ((trading cost) OR (training cost)) coping shu ;*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "yang yang yala ((hua credit) or (ida credits)) ((trading cost) OR (training cost)) coping shu ;*".