Perhaps you should try some spelling variations:
hanh trang » thanh trung, canh tranh, minh trang
hanh trinh » canh tranh, hanh chinh
doc chieu » doc hieu, toc thieu, hoc thieu
doi chieu » doc hieu, doi chi, ho chieu
song tac » cong tac, sang tac, dong tac
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan tap
va nang » van nang, da nang, cam nang

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

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