Perhaps you should try some spelling variations:
theo chieu » theo tieu, ho chieu, theo chu
hanh tranh » canh tranh, hanh trinh, hanh trang
thong cong » trong cong, tong cong, thong thong
doc hieu » toc thieu, hoc thieu, hoc hien
tranh va » tranh van, trang va, trinh va
va thong » va thuong, va phuong, he thong
tac toan » tam toan, hach toan, tich toan
tap toan » tap doan, tap quan, bai toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doc hieu) or (theo chieu)) xanh - hanh tranh va thong cong ((tac toan) OR (tap toan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (theo chieu)) xanh - hanh tranh va thong cong ((tac toan) OR (tap toan)) ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc hieu) or (theo chieu)) xanh - hanh tranh va thong cong ((tac toan) OR (tap toan)) ban".
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (theo chieu)) xanh - hanh tranh va thong cong ((tac toan) OR (tap toan)) ban*.