Perhaps you should try some spelling variations:
quan truong » quang truong, xuan truong, quang trung
chieu xanh » chieu sach, chieu sang, chieu tinh
quan trong » gian trong
hien xanh » hien hanh, hien nhanh, hien khanh
manh tung » manh hung, thanh tung
chung dan » chung han, hung dan, chung nhan
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.

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien xanh) OR (chieu xanh)) - manh tung ((quan truong) OR (quan trong)) chung dan toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hien xanh) or (chieu xanh)) - manh tung ((quan truong) OR (quan trong)) chung dan toan cao~".
• Adding a wildcard symbol may retrieve word variants: hoc ((hien xanh) or (chieu xanh)) - manh tung ((quan truong) OR (quan trong)) chung dan toan cao*.