Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
sang mai » sang ma, sang tai, lang mai
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cuu tre, dua tren
va daoh » va danh, va doanh
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
ky sang » ky nang, ky dang, ky tang
ve cac » va cac, vien cac
sac ky » cac ky, sai ky
va dao » ca dao
tu sac » tu sach, tu cac, tu san

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 ((va daoh) or (va dao)) lai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky sang mai hoi. hieu ve cac duc ((va daoh) OR (va dao)) lai ((cua tre) OR (cua triet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky sang mai hoi. hieu ve cac duc ((va daoh) or (va dao)) lai ((cua tre) OR (cua triet))*".