Perhaps you should try some spelling variations:
hien xanh » hien hanh, hien nhanh, chieu xanh
canh tinh » manh tinh, canh tranh, nhanh tinh
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
cong vang » cong quang, cong ngang, cong san
cong lang » cong luong, cong quang, cong ngang
toan cau » 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: hoc hien xanh - ((canh tinh) or (hanh tinh)) ung dung ((cong vang) OR (cong lang)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hien xanh - ((canh tinh) OR (hanh tinh)) ung dung ((cong vang) OR (cong lang)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hien xanh - ((canh tinh) or (hanh tinh)) ung dung ((cong vang) OR (cong lang)) toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc hien xanh - ((canh tinh) or (hanh tinh)) ung dung ((cong vang) OR (cong lang)) toan cau*.