Perhaps you should try some spelling variations:
doanh ban » doanh bat, doanh van, doanh nhan
doanh dan » doanh van, doanh dao, doanh doanh
hieu van » hieu va, thien van, lieu va
cac tuc » cac toc, cac tu, cac tac
van cac » van hac, van cau, van bac
sach ky » sac ky, sach y, sach kem
nang xa » nang x, lang xa, nang ma
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, truc va, tuc xa

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

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