Perhaps you should try some spelling variations:
theo chieu » theo tieu, theo chu, thi chieu
hanh trinh » canh tranh, hanh chinh
trinh cua » tinh cua, trinh luat, trinh quan
hang cong » dang cong, hang nong, bang cong
ho chieu » hoc thieu, doi chieu, mot chieu
cua hang » cua dang, cua nhung, cua cong
tap toan » tap doan, tap quan
bai toan » bai tap

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