Perhaps you should try some spelling variations:
trien hoat » tien hoa
quang quan » quang tuan, quang uan, quan quan
dung tang » dung thang, dung trang, dung dang
hieu suat » hieu luat, hieu qua
hien soat » thien hoat, kiem soat, bien soan
tang van » dang van, hoang van, trong van
van hieu » cao hieu
quan van » luan van, quan va, quan luan

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

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