Perhaps you should try some spelling variations:
cheng yang » cheng zhang, chen wang, cheng han
chen yang » chen rong
john song » john wong, john bonn, john ngosong
yan yang » yang yang, yao yang, dan yang
song sau » wong sau, kong sar, song pae
wan yan » wang yan, nan yan, wai yan
yang yu » yang yue, yang yun, yang yi

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

• Performing a fuzzy search may retrieve terms with similar spellings: wan yan yang yu ((cheng yang) or (chen yang)) john song sau ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wan yan yang yu ((cheng yang) OR (chen yang)) john song sau ;.
• Adding a wildcard symbol may retrieve word variants: wan yan yang yu ((cheng yang) or (chen yang)) john song sau ;*.