Perhaps you should try some spelling variations:
trien hoat » tien hoa
thien hoat » thien thuat, tien hoa
trinh dun » trinh dung, trinh dan, trinh den
hieu soat » hieu suat, hieu hoat, hieu luat
tinh dung » trinh dung, tin dung, tinh quang
dun nang » dung nang, den nang, luan nang
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 dun nang cao hieu soat ) or ( tinh dung luan van ((thien hoat) OR (trien hoat)) ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh dun nang cao hieu soat ) OR ( tinh dung luan van ((thien hoat) OR (trien hoat)) ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( trinh dun nang cao hieu soat ) or ( tinh dung luan van ((thien hoat) OR (trien hoat)) ))*".