Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
doi chieu » doc hieu, doi chi, mot chieu
cua thong » cua thuong, cua tong, suat thong
cua khong » hua khong, cua phuong, cua thuong
ho chieu » theo chieu, hoc thieu, mot chieu
cong bai » cuong bai, cong hai, cung bai
bai toan » bai tap
toan tap » toan ban

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 ((cua thong) OR (cua khong)) cong bai toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (doi chieu)) sach - hanh trinh ((cua thong) OR (cua khong)) cong bai toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (doi chieu)) sach - hanh trinh ((cua thong) OR (cua khong)) cong bai toan tap".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (doi chieu)) sach - hanh trinh ((cua thong) OR (cua khong)) cong bai toan tap*.