Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, nghiep nganh
nhung cong » dung cong, thong cong, hang cong
hieu manh » chieu xanh, dieu hanh, hien hanh
tranh cua » doanh cua, manh cua
cua nhung » va nhung
cong tac » cong ty
than cao » toan cao, than cap, than sao
thai cao » tai cao, thoai cac, thuat cao

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 tac ((than cao) OR (thai 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 tac ((than cao) OR (thai 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 tac ((than cao) OR (thai cao))".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) or (hieu nganh)) - canh tranh cua nhung cong tac ((than cao) OR (thai cao))*.