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

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tinh dung quang van hieu suat ) or ( tinh quang luan van ((kien soat) OR (kiem soat)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tinh dung quang van hieu suat ) OR ( tinh quang luan van ((kien soat) OR (kiem soat)) )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( tinh dung quang van hieu suat ) or ( tinh quang luan van ((kien soat) OR (kiem soat)) ))".
• Adding a wildcard symbol may retrieve word variants: (( tinh dung quang van hieu suat ) or ( tinh quang luan van ((kien soat) OR (kiem soat)) ))*.