Perhaps you should try some spelling variations:
quang quan » quang tuan, quang uan, quan quan
duong lang » duong dang, duong quang, duong thang
hieu suat » hieu luat, hieu qua
lang van » dang van, tang van, hoang van
quan van » luan van, quan va, quan luan
van ke » van ket, van de, van ky
toan » tran

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( dinh duong lang van ((thieu so) or (hieu suat)) ) or ( tinh quang quan van ke toan ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( dinh duong lang van ((thieu so) OR (hieu suat)) ) OR ( tinh quang quan van ke toan )).
• Adding a wildcard symbol may retrieve word variants: (( dinh duong lang van ((thieu so) or (hieu suat)) ) or ( tinh quang quan van ke toan ))*.