Perhaps you should try some spelling variations:
quang tang » quang thang, quang dang, quang tung
vinh thang » dinh thang, dinh thanh, vinh hung
thang luan » tang luan, hang luan, thong luan
hieu suat » hieu luat, hieu qua
hien soan » bien soan, thien toan, dien toan
tang van » dang van, hoang van, trong van
van hieu » cao hieu
van hien » van tien
tinh » trinh, dinh, minh

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh quang tang van hieu suat ) or ( vinh thang luan van hien soan ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh quang tang van hieu suat ) OR ( vinh thang luan van hien soan ))*.