Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hoc hieu » hoc thieu, hoc hien, hoc dieu
doc hieu » toc thieu, hoc thieu, hoc hien
tram van » tran van, trang van, tranh van
cong san » cong tac
san than » sang than, san thanh, ban than
than cao » toan cao, thai cao, than cap
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) OR (doc hieu)) nganh - hanh ((tram van) OR (tam van)) nhung cong san than cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc hieu) OR (doc hieu)) nganh - hanh ((tram van) or (tam van)) nhung cong san than cao~".
• Adding a wildcard symbol may retrieve word variants: ((hoc hieu) OR (doc hieu)) nganh - hanh ((tram van) or (tam van)) nhung cong san than cao*.