Perhaps you should try some spelling variations:
quang luan » quan luan, quang tuan, quang uan
hieu soat » hieu suat, hieu luat, kiem soat
hieu hoat » hieu hoa, thien hoat, hieu luat
luan viet » luat viet, xuan viet, quan viet
viet lieu » vat lieu, viet tien, viet viet
lieu so » hieu so, thieu so, lieu hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( (minh or trinh) quang luan van ((hieu soat) OR (hieu hoat)) ) or ( tin dung luan viet lieu so ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( (minh OR trinh) quang luan van ((hieu soat) OR (hieu hoat)) ) OR ( tin dung luan viet lieu so )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( (minh or trinh) quang luan van ((hieu soat) OR (hieu hoat)) ) or ( tin dung luan viet lieu so ))".
• Adding a wildcard symbol may retrieve word variants: (( (minh or trinh) quang luan van ((hieu soat) OR (hieu hoat)) ) or ( tin dung luan viet lieu so ))*.