Perhaps you should try some spelling variations:
yang yang » wang yan
wang yang » wang yan, wang liang, wang yanling
sang minh » kang minah, anh minh, song min
hong than » hong tan, long thanh
yao chai » hao chi, ka chai
chai dan » chai onn, chai tam, shi dan
dan sang » dan yang, dan dana, dan qing
hong hai » shang hai, zhong tai, dang hai

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: ((yang yang) OR (wang yang)) yao chai dan sang minh ((hong hai) OR (hong than)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((yang yang) OR (wang yang)) yao chai dan sang minh ((hong hai) or (hong than)) ;~".
• Adding a wildcard symbol may retrieve word variants: ((yang yang) OR (wang yang)) yao chai dan sang minh ((hong hai) or (hong than)) ;*.