Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
nhung cong » dung cong, thong cong, hang cong
doi chieu » doc hieu, doi chi, mot chieu
van thanh » ban thanh, van tuan
ho chieu » theo chieu, hoc thieu, mot chieu
trinh va » trinh van, trinh vat, trinh ve
dan toan » van toan, dan than, manh toan

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

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