Perhaps you should try some spelling variations:
quang tran » quang tuan, quang trung, quang thanh
dung taid » dung sai, dung tri, dung hai
hieu suat » hieu luat, hieu qua
van hieu » cao hieu
tran van » luan van
van hien » van tien
hien hoa » hien khoa, dien hoa, tien hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( trinh ((dung tai) or (dung taid)) van hieu suat ) or ( tinh quang tran van hien hoa ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh ((dung tai) OR (dung taid)) van hieu suat ) OR ( tinh quang tran van hien hoa )).
• Adding a wildcard symbol may retrieve word variants: (( trinh ((dung tai) or (dung taid)) van hieu suat ) or ( tinh quang tran van hien hoa ))*.