Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, hieu lang
hien xanh » hien hanh, hien nhanh, chieu xanh
hanh tang » hanh trang, anh tang, hanh mang
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
toan cau » toan cao, toan ban, toan tap
tang va » trang va, tang van, thang va

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 sang)) - hanh tang va nhung ((cong dan) or (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien xanh) OR (chieu sang)) - hanh tang va nhung ((cong dan) OR (cong san)) toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((hien xanh) or (chieu sang)) - hanh tang va nhung ((cong dan) or (cong san)) toan cau*.