Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hanh trang » thanh trung, canh tranh, hanh trinh
theo hieu » theo chieu, thien hieu, thuc hieu
hanh tang » anh tang, hanh mang, hanh tung
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan cau » 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: ((theo hieu) OR (theo tieu)) lang - ((hanh tang) OR (hanh trang)) va nhung cong san toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((theo hieu) OR (theo tieu)) lang - ((hanh tang) or (hanh trang)) va nhung cong san toan cau~".
• Adding a wildcard symbol may retrieve word variants: ((theo hieu) OR (theo tieu)) lang - ((hanh tang) or (hanh trang)) va nhung cong san toan cau*.