Perhaps you should try some spelling variations:
hieu nganh » vien nganh, hiem ngan, hieu manh
nhung cong » thong cong, hang cong, nhung don
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
tram van » tran van, trang van, tranh van
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 nganh - hanh ((tram van) OR (tam van)) ((nhung cong) OR (dung cong)) san than 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) OR (dung cong)) san than cao~".
• Adding a wildcard symbol may retrieve word variants: hoc hieu nganh - hanh ((tram van) or (tam van)) ((nhung cong) OR (dung cong)) san than cao*.