Perhaps you should try some spelling variations:
doi chieu » doi chi, ho chieu, mot chieu
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap
va bang » va nang, va lang, va hang
va ban » van ban, va bai, va bao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((doi chieu) OR (doc hieu)) sang - canh tranh ((va bang) or (va ban)) cong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (doc hieu)) sang - canh tranh ((va bang) OR (va ban)) cong dan toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) OR (doc hieu)) sang - canh tranh ((va bang) or (va ban)) cong dan toan cao".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) OR (doc hieu)) sang - canh tranh ((va bang) or (va ban)) cong dan toan cao*.