Perhaps you should try some spelling variations:
tcanh tranh » thanh thanh, can tranh, lanh tranh
phuong dong » phuong dung, phuong hoang, chuong duong
thieu xanh » hieu manh, thien anh, thien danh
chieu xanh » chieu sach, chieu sang, chieu tinh
van phuong » van phong, va phuong, van chuong
toan cau » toan cao, toan ban, toan tap
dong so » dong son, dong co, cong so
so toan » so tan, so than, bao toan

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 tranh) OR (tcanh tranh)) van phuong dong so toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu xanh) OR (chieu xanh)) - ((canh tranh) or (tcanh tranh)) van phuong dong so toan cau~".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) OR (chieu xanh)) - ((canh tranh) or (tcanh tranh)) van phuong dong so toan cau*.