Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
dua ban » dia ban, cua ban, mua ban
tai cua » thai cua, tai cuc, tri cua
qua ban » cua ban, qua quan
sach ky » sac ky, sach y, sach ty
van lam » van nam
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
cua tre » cua te, cuu tre, cua triet

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 ((nang ma) OR (tang ma)) hoa. hieu van lam ((dua ban) or (qua ban)) thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang ma) OR (tang ma)) hoa. hieu van lam ((dua ban) OR (qua ban)) thanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang ma) OR (tang ma)) hoa. hieu van lam ((dua ban) or (qua ban)) thanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang ma) OR (tang ma)) hoa. hieu van lam ((dua ban) or (qua ban)) thanh tai cua tre*.