Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
va daoh » va danh, va doanh
ky sang » ky nang, ky dang, ky tang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
hai cua » thai cua, dai cua, hoi cua
cac duc » cao duc, cac dac, cac nuoc
tu sac » tu sach, tu cac, tu san
va dao » ca dao
cua te » cua tu
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky sang mai hoi. hieu ve ((cac duc) OR (cac du)) ((va daoh) or (va dao)) hai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky sang mai hoi. hieu ve ((cac duc) OR (cac du)) ((va daoh) OR (va dao)) hai cua te*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky sang mai hoi. hieu ve ((cac duc) OR (cac du)) ((va daoh) or (va dao)) hai cua te*".