Perhaps you should try some spelling variations:
dung quang » dang quang, dung quan, luong quang
quang van » quang ban, quan van, quang uan
hieu suat » hieu luat, hieu qua
tinh quan » tinh quang, trinh quan, tin quan
kien soat » kiem soat, kien hoa, dien hoat
bien soan » bien so
van hieu » cao hieu
luan » lan

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 quang van hieu suat ) or ( tinh quan luan van ((kien soat) or (bien soan)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung quang van hieu suat ) OR ( tinh quan luan van ((kien soat) OR (bien soan)) )).
• Adding a wildcard symbol may retrieve word variants: (( tin dung quang van hieu suat ) or ( tinh quan luan van ((kien soat) or (bien soan)) ))*.