Perhaps you should try some spelling variations:
quang quan » quang tuan, quang uan, quan quan
trien hoat » tien hoa
dung lang » dung dang, dung nang, dung land
hieu suat » hieu luat, hieu qua
hien soat » thien hoat, kiem soat, bien soan
lang van » dang van, tang van, hoang van
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: (( tin dung lang van hieu suat ) or ( tinh quang quan luan ((hien soat) or (trien hoat)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung lang van hieu suat ) OR ( tinh quang quan luan ((hien soat) OR (trien hoat)) )).
• Adding a wildcard symbol may retrieve word variants: (( tin dung lang van hieu suat ) or ( tinh quang quan luan ((hien soat) or (trien hoat)) ))*.