Perhaps you should try some spelling variations:
doanh dan » doanh ban, doanh van, doanh doanh
doanh dao » doanh bao, doanh cao, doanh giao
te sach » toc sach
cac tac » cac toc, cac bac, cac dac
tac van » tac vang, cac van, tac va
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
hieu ve » hieu van
dang ha » dong ha, dung ha, lang ha
ky dang » ky nang, ky danh
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, xa hoi

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky dang ha hoi. ((hieu ve) or (hieu va)) cac tac van ((doanh dan) OR (doanh dao)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky dang ha hoi. ((hieu ve) OR (hieu va)) cac tac van ((doanh dan) OR (doanh dao)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky dang ha hoi. ((hieu ve) or (hieu va)) cac tac van ((doanh dan) OR (doanh dao)) cua tre*".