Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
ban thanh » ban hanh, ban hang
su viet » so viet
duc ban » duc tan, duc van, dua ban
tang ma » tang van
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
dao duc » giao duc, tao duoc
su sai » su tai, su hai, su dai
sai ky » sac ky
ve dao » de dao, va dao, ve bao

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sai ky ((tang ma) or (mang may)) hoi. hieu ve dao duc ban thanh dai ((cua tre) or (su viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sai ky ((tang ma) OR (mang may)) hoi. hieu ve dao duc ban thanh dai ((cua tre) OR (su viet)).
• Adding a wildcard symbol may retrieve word variants: su sai ky ((tang ma) or (mang may)) hoi. hieu ve dao duc ban thanh dai ((cua tre) or (su viet))*.