Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, hieu manh
nhung cong » dung cong, thong cong, hang cong
tranh cua » doanh cua, manh cua
cua nhung » va nhung
hoc hieu » hoc thieu, hoc hien, doc hieu
tac toan » tam toan, hach toan, tich toan
tap toan » tap doan, tap quan, bai toan

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: hoc hieu nganh - canh tranh cua nhung cong ((((tac toan) OR (tinh toan))) OR (tap toan)) cau~.
• Adding a wildcard symbol may retrieve word variants: hoc hieu nganh - canh tranh cua nhung cong ((((tac toan) or (tinh toan))) or (tap toan)) cau*.