Perhaps you should try some spelling variations:
doi chieu » doi chi, ho chieu, mot chieu
tang luan » dung luan
luan nang » luan van, van nang, luan san
doc hieu » toc thieu, hoc thieu, hoc hien
anh tang » anh bang, anh dang, anh nang
dan toan » van toan, manh toan, xuan toan
dan than » dan chan, ban than, van than

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doi chieu) OR (doc hieu)) sach - anh tang luan nang song ((dan toan) or (dan than)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (doc hieu)) sach - anh tang luan nang song ((dan toan) OR (dan than)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) OR (doc hieu)) sach - anh tang luan nang song ((dan toan) or (dan than)) cau".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) OR (doc hieu)) sach - anh tang luan nang song ((dan toan) or (dan than)) cau*.