Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, nghiep nganh
hieu manh » chieu xanh, dieu hanh, hien hanh
hang hang » nang hang, cang thang, hung thang
thanh cau » thanh chau, thanh mau, nhanh cau
cong tan » cong tac, cong san, cong thanh
song van » hoang van, trong van, duong van
va dung » van dung, va duong, vat dung

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 manh) OR (hieu nganh)) - hang hang va dung ((cong tan) OR (song van)) thanh cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu manh) OR (hieu nganh)) - hang hang va dung ((cong tan) or (song van)) thanh cau~".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) OR (hieu nganh)) - hang hang va dung ((cong tan) or (song van)) thanh cau*.