Perhaps you should try some spelling variations:
chieu xanh » chieu sang, chieu tinh, hieu manh
chieu sach » chinh sach, chiet tach, chieu sang
hanh trinh » canh tranh, hanh chinh
nhung cong » dung cong, thong cong, hang cong
trinh ve » trinh he, trinh va, trinh vi
ve nhung » va nhung, tu nhung
san toan » van toan, manh toan, xuan toan
dan toan » van toan, dan than, manh toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu xanh) or (chieu sach)) - hanh trinh ve nhung cong ((san toan) OR (dan toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu xanh) OR (chieu sach)) - hanh trinh ve nhung cong ((san toan) OR (dan toan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu xanh) or (chieu sach)) - hanh trinh ve nhung cong ((san toan) OR (dan toan)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu xanh) or (chieu sach)) - hanh trinh ve nhung cong ((san toan) OR (dan toan)) cao*.