Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
dua ban » dia ban, cua ban, qua ban
van cac » van hac, van cau, van bac
sach ky » sac ky, sach y, sach ty
te sach » toc sach
ky tang » ky nang, ky dang, kho tang
cua tre » cua te, cuu tre, cua triet
du ban » duc ban, du bao, tu ban
ma hoi » mai hoi, xa hoi, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky tang ((ma hoi) or (ma hoa)). hieu van cac ((du ban) OR (dua ban)) thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky tang ((ma hoi) OR (ma hoa)). hieu van cac ((du ban) OR (dua ban)) thanh dai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky tang ((ma hoi) or (ma hoa)). hieu van cac ((du ban) OR (dua ban)) thanh dai cua tre*".