Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
trong ban » trong san, trong tan, trong quan
ho chieu » theo chieu, hoc thieu, doi chieu
cua dung » cua dang, qua dung, cua rung
cua dong » chua dong, cua cong, cua dang
ban toan » bai toan, ban than, van toan
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 (hoc hien)) xanh - hanh tranh ((cua dung) OR (cua dong)) trong ban toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (hoc hien)) xanh - hanh tranh ((cua dung) OR (cua dong)) trong ban toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (hoc hien)) xanh - hanh tranh ((cua dung) OR (cua dong)) trong ban toan cao".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (hoc hien)) xanh - hanh tranh ((cua dung) OR (cua dong)) trong ban toan cao*.