Perhaps you should try some spelling variations:
doanh van » doan van, doanh va, doanh nhan
doanh ban » doanh bat, doanh nhan, doanh luan
cua triet » cua viet, su triet, va triet
thu sach » tu sach, thuat sach, thuoc sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
co hoi » co hoc
va am » va lam, va cam

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

• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((co hoi) OR (co loi)). hieu va am thuc va ((doanh van) OR (doanh ban)) cua triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang ((co hoi) OR (co loi)). hieu va am thuc va ((doanh van) or (doanh ban)) cua triet~".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((co hoi) OR (co loi)). hieu va am thuc va ((doanh van) or (doanh ban)) cua triet*.