Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hieu tinh » chieu tinh, lieu tinh, kieu tinh
vat thong » vat trong, mat thong, vat khong
doc hieu » toc thieu, hoc thieu, hoc hien
va thong » va thuong, va phuong, he thong
dan toan » van toan, dan than, manh toan
van tuan » van quan, van ban, anh tuan

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

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