Perhaps you should try some spelling variations:
duong luan » dung luan, dong luan, duong quan
trinh quan » tinh quang, trinh luat, trinh han
lien soat » kiem soat, bien soan, lien son
hieu soat » hieu suat, hieu hoat, hieu luat
van hieu » cao hieu
quan va » quan vi, quan ha, quan ve
luan va » luat va

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

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