Perhaps you should try some spelling variations:
yang yang » wang yan
wang yang » wang yan, wang liang, wang yanling
than data » than death, loan data, can data
sang minh » kang minah, anh minh, song min
than bau » than bad, than a, than you
minh how » mind how, minh hoa, myth how
how ai » how aid, how ae, how am

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