Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
luong cong » dung cong, trong cong, cong cong
hieu lang » chieu sang, nhieu tang, hieu van
cong san » cong tac
san than » sang than, san thanh, ban than
than cau » toan cau, phan cau, than cap
luan » quan, lan

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: theo ((hieu lang) OR (hieu quang)) - hanh ((tran van) OR (luan van)) luong cong san than cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((hieu lang) OR (hieu quang)) - hanh ((tran van) or (luan van)) luong cong san than cau~".
• Adding a wildcard symbol may retrieve word variants: theo ((hieu lang) OR (hieu quang)) - hanh ((tran van) or (luan van)) luong cong san than cau*.