Perhaps you should try some spelling variations:
hanh tranh » hanh trinh, hanh trang, lanh tranh
hieu xanh » chieu xanh, hieu manh, hieu nganh
doc hieu » toc thieu, hoc thieu, hoc hien
ban cong » bang cong, phan cong, ban huong
van cong » van dong, van phong, phan cong
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: doc hieu xanh - ((hanh tranh) OR (canh tranh)) van ((ban cong) OR (van cong)) dan toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - ((hanh tranh) or (canh tranh)) van ((ban cong) OR (van cong)) dan toan cao~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - ((hanh tranh) or (canh tranh)) van ((ban cong) OR (van cong)) dan toan cao*.