Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, hieu lang
nhung cong » dung cong, thong cong, hang cong
hieu manh » chieu xanh, hieu nganh, dieu hanh
trung cap » truong cao
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
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 ((hieu manh) or (chieu sang)) - hanh ((trung cap) OR (trung tam)) nhung cong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu manh) OR (chieu sang)) - hanh ((trung cap) OR (trung tam)) nhung cong dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu manh) or (chieu sang)) - hanh ((trung cap) OR (trung tam)) nhung cong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu manh) or (chieu sang)) - hanh ((trung cap) OR (trung tam)) nhung cong dan toan cau*.