Perhaps you should try some spelling variations:
thanh doanh » hanh doanh, thanh toan, chinh doanh
doanh cua » doanh luan
ban thanh » ban hanh, ban hang
hieu van » thien van, lieu va, hieu ve
day ban » tay ban, da ban, day dan
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach kem
sang ma » tang ma, nang ma, sang tao
sach ty » sach y, sach tu, sach thu
ca day » cam day, ca dao, ca dan

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 ty)) sang ma hoa. ((hieu van) OR (hieu va)) ca day ban thanh doanh cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach ty)) sang ma hoa. ((hieu van) OR (hieu va)) ca day ban thanh doanh cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach ty)) sang ma hoa. ((hieu van) OR (hieu va)) ca day ban thanh doanh cua tre*".