Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, nghiep nganh
nhung cong » thong cong, hang cong, nhung don
hieu manh » chieu xanh, dieu hanh, hien hanh
tranh cua » doanh cua, manh cua
dung cong » dung trong
tac than » tac thanh, tam than, tac nhan
than cao » toan cao, thai cao, than cap

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu manh) or (hieu nganh)) - canh tranh cua ((nhung cong) OR (dung cong)) tac than cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu manh) OR (hieu nganh)) - canh tranh cua ((nhung cong) OR (dung cong)) tac than cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu manh) or (hieu nganh)) - canh tranh cua ((nhung cong) OR (dung cong)) tac than cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) or (hieu nganh)) - canh tranh cua ((nhung cong) OR (dung cong)) tac than cao*.