Perhaps you should try some spelling variations:
theo chieu » theo tieu, ho chieu, theo chu
phuong dan » phuong danh, phuong doan, huong dan
canh tran » canh tranh, hanh trang, banh trang
doc hieu » toc thieu, hoc thieu, hoc hien
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan tap
van ngu » van nga, van ngo, van nu
han ngu » nhat ngu

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) OR (theo chieu)) xanh - canh tran ((van ngu) OR (han ngu)) phuong dan toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doc hieu) or (theo chieu)) xanh - canh tran ((van ngu) OR (han ngu)) phuong dan toan cau~".
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (theo chieu)) xanh - canh tran ((van ngu) OR (han ngu)) phuong dan toan cau*.