Perhaps you should try some spelling variations:
chieu xanh » chieu sach, chieu sang, chieu tinh
hien xanh » hien hanh, hien nhanh, hien khanh
tranh cua » doanh cua, manh cua
hang cong » dang cong, hang nong, bang cong
cua hang » cua dang, cua nhung, cua cong
tap toan » tap doan, tap quan
bai toan » bai tap

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)) - canh tranh cua hang cong ((tap toan) OR (bai toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien xanh) OR (chieu xanh)) - canh tranh cua hang cong ((tap toan) OR (bai toan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien xanh) or (chieu xanh)) - canh tranh cua hang cong ((tap toan) OR (bai toan)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien xanh) or (chieu xanh)) - canh tranh cua hang cong ((tap toan) OR (bai toan)) cao*.