Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu qua, diep quang
nhung cong » dung cong, thong cong, hang cong
hieu quan » hieu qua, lieu quan, thien quan
hanh hang » thanh hang, hang hang, hanh han
cua nhung » va nhung
hang cua » mang cua, hang ca, huong cua
dan than » dan chan, ban than, van than

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((hieu quang) or (hieu quan)) - hanh hang cua nhung cong ((dan than) or (dan gian)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu quang) OR (hieu quan)) - hanh hang cua nhung cong ((dan than) OR (dan gian)) cau.
• Adding a wildcard symbol may retrieve word variants: doc ((hieu quang) or (hieu quan)) - hanh hang cua nhung cong ((dan than) or (dan gian)) cau*.