Perhaps you should try some spelling variations:
thieu xanh » hieu manh, thien anh, thien danh
chieu xanh » chieu sach, chieu sang, chieu tinh
nhung cong » dung cong, thong cong, nhung don
canh tran » canh tranh, hanh trang, banh trang
hang cong » dang cong, hang nong, bang cong
tran van » luan van
san toan » van toan, dan toan, manh toan
toan tap » toan ban

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) OR (chieu xanh)) - canh tran van ((nhung cong) OR (hang cong)) san toan tap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu xanh) or (chieu xanh)) - canh tran van ((nhung cong) OR (hang cong)) san toan tap~".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) or (chieu xanh)) - canh tran van ((nhung cong) OR (hang cong)) san toan tap*.