Perhaps you should try some spelling variations:
hieu soat » hieu suat, hieu hoat, kiem soat
hieu luat » hieu qua
quang tan » quang tuan, quang tran, quang toan
van dien » van tien, van hien, van kien
dien hat » dien hoat, dien nhat, dieu hat
tan van » tran van, tang van, dang van
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 dung luan van ((hieu soat) OR (hieu luat)) ) or ( tinh quang tan van dien hat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh dung luan van ((hieu soat) OR (hieu luat)) ) OR ( tinh quang tan van dien hat )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( trinh dung luan van ((hieu soat) OR (hieu luat)) ) or ( tinh quang tan van dien hat ))".
• Adding a wildcard symbol may retrieve word variants: (( trinh dung luan van ((hieu soat) OR (hieu luat)) ) or ( tinh quang tan van dien hat ))*.