Perhaps you should try some spelling variations:
dung quan » dung quang, dung luan, luong quan
hieu suat » hieu luat, hieu qua
tinh nang » trinh nang, tin nang, tich nang
nang quan » ban quan, nang suat
binh hien » minh hien, kinh hien, tinh hien
dinh hien » dinh chien, dinh dien, minh hien
quan van » luan van, quan va, quan luan
van hieu » cao hieu

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 quan van hieu suat ) or ( tinh nang quan ((binh hien) OR (dinh hien)) soat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh dung quan van hieu suat ) OR ( tinh nang quan ((binh hien) OR (dinh hien)) soat )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( trinh dung quan van hieu suat ) or ( tinh nang quan ((binh hien) OR (dinh hien)) soat ))".
• Adding a wildcard symbol may retrieve word variants: (( trinh dung quan van hieu suat ) or ( tinh nang quan ((binh hien) OR (dinh hien)) soat ))*.