Perhaps you should try some spelling variations:
tuong quan » truong quan, thong quan, luong quan
kien soat » kiem soat, bien soan, kien hoa
tin tuong » tin thuong, tin huong, tin trong
dieu soat » kiem soat, hieu suat, dieu hoa
tuan van » luan van, tran van, quan van
tan van » tran van, tang van, luan van
quan va » quan vi, quan ha, luan va
tinh » trinh, dinh, minh

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

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