Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, nghiep nganh
hanh tranh » canh tranh, hanh trinh, hanh trang
hieu manh » chieu xanh, dieu hanh, hien hanh
cua tong » cua cong, cua nong, cua song
cua dong » chua dong, cua cong, cua dang
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan cao » toan ban, toan tap

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)) - hanh tranh ((cua tong) OR (cua dong)) cong tap toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu manh) OR (hieu nganh)) - hanh tranh ((cua tong) OR (cua dong)) cong tap toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu manh) or (hieu nganh)) - hanh tranh ((cua tong) OR (cua dong)) cong tap toan cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) or (hieu nganh)) - hanh tranh ((cua tong) OR (cua dong)) cong tap toan cao*.