Perhaps you should try some spelling variations:
trinh thanh » tinh thanh, trinh han, trinh toan
theo chieu » theo tieu, theo chu, thi chieu
hanh trinh » canh tranh, hanh chinh
hang cong » hang nong, bang cong, thanh cong
dang cong » dung cong
ho chieu » hoc thieu, doi chieu, mot chieu
tap toan » tap doan, tap quan, bai toan
toan ban » van 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 (theo chieu)) sach - hanh trinh thanh ((hang cong) OR (dang cong)) tap toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (theo chieu)) sach - hanh trinh thanh ((hang cong) OR (dang cong)) tap toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (theo chieu)) sach - hanh trinh thanh ((hang cong) OR (dang cong)) tap toan ban".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (theo chieu)) sach - hanh trinh thanh ((hang cong) OR (dang cong)) tap toan ban*.