Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh tai » thanh hai, thanh toan, doanh tai
sach thu » sach thue, sach thieu, sach tham
tai cua » thai cua, tai cuc, tri cua
duc ban » duc tan, duc van, dua ban
va chat » van chat, va phat, hoa chat
sach ty » sach y, sach tu, xach tay
tang ma » mang may, tang van
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: su ((sach ty) OR (sach thu)) tang ma hoa. hieu ((va chat) or (cao chat)) duc ban thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach thu)) tang ma hoa. hieu ((va chat) OR (cao chat)) duc ban thanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach thu)) tang ma hoa. hieu ((va chat) or (cao chat)) duc ban thanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach thu)) tang ma hoa. hieu ((va chat) or (cao chat)) duc ban thanh tai cua tre*.