Perhaps you should try some spelling variations:
hanh huong » thanh huong, anh huong, manh huong
thong cong » trong cong, tong cong, phong chong
doi chieu » doc hieu, doi chi, mot chieu
huong cua » dung cua
ho chieu » theo chieu, hoc thieu, mot chieu
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan 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 (doi chieu)) xanh - hanh huong cua ((thong cong) OR (thong thong)) tac toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (doi chieu)) xanh - hanh huong cua ((thong cong) OR (thong thong)) tac toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (doi chieu)) xanh - hanh huong cua ((thong cong) OR (thong thong)) tac toan cau".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (doi chieu)) xanh - hanh huong cua ((thong cong) OR (thong thong)) tac toan cau*.