Perhaps you should try some spelling variations:
doanh van » doanh va, doanh ban, doanh nhan
hieu van » hieu va, thien van, lieu va
doan van » doan va, hoang van, luan van
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
van cau » van dau, van hau, van chat
cau luc » cau truc, cau phuc
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va
x hoi » xa hoi, o hoi, x ho

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 nang x hoi. hieu van cau luc va ((doanh van) OR (doan van)) ((cua tre) or (cua viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. hieu van cau luc va ((doanh van) OR (doan van)) ((cua tre) OR (cua viet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. hieu van cau luc va ((doanh van) OR (doan van)) ((cua tre) or (cua viet))*".