Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu sang, chieu tinh
hanh trinh » canh tranh, hanh chinh
khong cong » thong cong, chong cong, khong con
khong cang » thong cong, hong bang, khong dung
hien xanh » hien hanh, hien nhanh, hien khanh
trinh hoa » trinh do, trinh han
san toan » van toan, dan toan, manh toan
toan ban » van ban

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

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