Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh tai » thanh hai, thanh toan, doanh tai
hieu van » hieu va, thien van, lieu va
sach thu » sach thue, sach thieu, sach tham
tai cua » thai cua, tai cuc, tri cua
dua ban » dia ban, cua ban, qua ban
cam dua » ca dua, cay dua, chay dua
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
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: tu ((sach ky) or (sach thu)) nang ((ma hoi) or (ma hoa)). hieu van cam dua ban thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach thu)) nang ((ma hoi) OR (ma hoa)). hieu van cam dua ban thanh tai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach thu)) nang ((ma hoi) or (ma hoa)). hieu van cam dua ban thanh tai cua tre*.