Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
manh tuong » manh tung, manh cuong, minh tuong
nhung cong » dung cong, thong cong, hang cong
tang luan » dung luan
hoc hieu » hoc thieu, hoc hien, doc hieu
tuong va » truong va, thuong va, luong va
tan luan » toan luan, san luan, han luan
dan luan » doanh luan, dung luan, hang luan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu quang - manh tuong va nhung cong ((tan luan) or (((dan luan) OR (tang luan)))) van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu quang - manh tuong va nhung cong ((tan luan) OR (((dan luan) OR (tang luan)))) van.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu quang - manh tuong va nhung cong ((tan luan) or (((dan luan) OR (tang luan)))) van".
• Adding a wildcard symbol may retrieve word variants: hoc hieu quang - manh tuong va nhung cong ((tan luan) or (((dan luan) OR (tang luan)))) van*.