Perhaps you should try some spelling variations:
quang tuan » quang thanh, quan luan, quang cua
tinh dung » trinh dung, tin dung, tinh huong
hieu soat » hieu hoat, hieu luat, hieu so
hieu suat » hieu luat, hieu qua
kiem soat » kiem toan
tuan van » luan van, tran van, tan van
van kiem » va kiem, van kien, van hieu

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

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