Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
doi chieu » doc hieu, ho chieu, mot chieu
hanh tang » hanh trang, anh tang, hanh mang
dan toan » van toan, manh toan, xuan toan
dan than » dan chan, ban than, van than
doi chi » doi khi
tang va » trang va, tang van, thang va

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 (doi chi)) sach - hanh tang va nhung cong ((dan toan) or (dan than)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (doi chi)) sach - hanh tang va nhung cong ((dan toan) OR (dan than)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) OR (doi chi)) sach - hanh tang va nhung cong ((dan toan) or (dan than)) cau".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) OR (doi chi)) sach - hanh tang va nhung cong ((dan toan) or (dan than)) cau*.