Perhaps you should try some spelling variations:
lang quang » hang quang, long quang, tang quang
dang quang » dung quang, nang quan, dang hung
thanh tien » thanh vien, thanh nien, thang tien
hieu soat » hieu suat, hieu hoat, hieu luat
tien soat » trien hoat, thien hoat, kiem soat
van hieu » cao hieu
tin » tinh
luan » quan, lan

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

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