Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
tu sach » su sach, te sach, tu cach
dua ban » dia ban, cua ban, mua ban
van cua » vang cua, ban cua, dan cua
qua ban » cua ban, qua quan
van lam » van nam
tang ma » mang may, tang van
cua tre » cua te, cuu tre, cua triet
y tang » ky tang, 6 tang, 7 tang

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