Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
trang cua » tranh cua, tang cua, trung cua
doanh cua » doanh luan
doc hiem » doc hieu, hoc hien, dat hiem
doc viet » duoc viet, hoc viet, toc viet
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan tap

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: ((doc hiem) OR (doc viet)) ngan - hanh ((trang cua) OR (doanh cua)) nhung cong tac toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc hiem) OR (doc viet)) ngan - hanh ((trang cua) or (doanh cua)) nhung cong tac toan cau~".
• Adding a wildcard symbol may retrieve word variants: ((doc hiem) OR (doc viet)) ngan - hanh ((trang cua) or (doanh cua)) nhung cong tac toan cau*.