Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
ban thanh » ban hanh, ban hang
dang xay » dang van, van xay
tai cua » thai cua, tai cuc, tri cua
duc ban » duc tan, duc van, dua ban
cac duc » cac du, cao duc, cac dac
qua cac » cua cac
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, lang van
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: tu sach ty ((tang ma) or (((lang xa) OR (dang xay)))) hoi. hieu qua cac duc ban thanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((tang ma) OR (((lang xa) OR (dang xay)))) hoi. hieu qua cac duc ban thanh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((tang ma) or (((lang xa) OR (dang xay)))) hoi. hieu qua cac duc ban thanh tai cua tre*".