Perhaps you should try some spelling variations:
quang uan » quang tuan, quang ban, quang tran
hieu suat » hieu luat, hieu qua
kien soat » kiem soat, bien soan, kien hoa
van kien » van tien, van hien, van chien
lan van » luan van, lang van, san van
tan van » tran van, tang van, luan van
uan van » luan van, quan van, san van

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