Perhaps you should try some spelling variations:
nang quang » nang quan, dang quang, hang quang
hieu soat » hieu suat, hieu hoat, hieu luat
van hieu » cao hieu
tin nang » tin dung, ki nang, thi nang
vat bien » vat lieu, cam bien
va bien » va lien, va dien, cam bien
luan » quan, lan

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( trinh dung luan van hieu soat ) or ( tin nang quang ((va bien) or (vat bien)) soan ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh dung luan van hieu soat ) OR ( tin nang quang ((va bien) OR (vat bien)) soan )).
• Adding a wildcard symbol may retrieve word variants: (( trinh dung luan van hieu soat ) or ( tin nang quang ((va bien) or (vat bien)) soan ))*.