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