Perhaps you should try some spelling variations:
thang luan » tang luan, hang luan, thong luan
vinh thang » dinh thang, dinh thanh, vinh hung
quang tan » quang tuan, quang tran, quang toan
hieu suat » hieu luat, hieu qua
bien soan » bien so
van hieu » cao hieu
van bien » van tien, van hien, vat bien
tan van » tran van, tang van, dang van
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 tan van hieu suat ) or ( vinh thang luan van bien soan ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh quang tan van hieu suat ) OR ( vinh thang luan van bien soan ))*.