Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, hieu manh
nhung cong » dung cong, thong cong, hang cong
hoc hieu » hoc thieu, hoc hien, doc hieu
tram van » tran van, trang van, tranh van
cong san » cong tac
than cao » thai cao, than cap, than sao
toan cao » toan ban, toan tap
tam van » nam van, dam van, tom van

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 - hanh ((tram van) OR (tam van)) nhung cong san ((than cao) OR (toan cao))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu nganh - hanh ((tram van) or (tam van)) nhung cong san ((than cao) OR (toan cao))~".
• Adding a wildcard symbol may retrieve word variants: hoc hieu nganh - hanh ((tram van) or (tam van)) nhung cong san ((than cao) OR (toan cao))*.