Perhaps you should try some spelling variations:
training visit » training crisis, training asia, training vet
trading case » trading costs, trade case
hua credit » dual credit, a credit, du credit
yang yang » wang yang, wang yan
yang yi » yang di, yang xi, yang jui
hong yu » wong yue
yi hua » li hua, ya hua, yi hui

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 yi hua credit ((trading case) or (training visit)) hong yu ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: yang yang yi hua credit ((trading case) OR (training visit)) hong yu ;.
• Adding a wildcard symbol may retrieve word variants: yang yang yi hua credit ((trading case) or (training visit)) hong yu ;*.