Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
hanh trang » thanh trung, hanh trinh, minh trang
hoc thieu » toc thieu, hoc hien
dung cong » dung trong
cong dan » cong san, cong tan, huong dan
than cao » thai cao, than cap, than sao
toan cao » toan ban, toan tap
va dung » van dung, va duong, vat dung

You may be able to get more results by adjusting your search query.

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