Perhaps you should try some spelling variations:
"nguyen can trinh thuc" » "nguyen can trinh tu", "nguyen can trinh thi", "nguyen van trinh thuc", "nguyen xuan trinh thuc", "nguyen cong trinh thuc", "nguyen can tranh thuc", "nguyen dan trinh thuc"
"nguyen can tinh thue" » "nguyen van tinh thue", "nguyen xuan tinh thue", "nguyen cong tinh thue", "nguyen can tinh thua", "nguyen can trinh thuy", "nguyen can tinh phu", "nguyen canh tinh thue", "nguyen ban tinh thue", "nguyen cac tinh thue"
"nguyen thi minh khue" » "nguyen chi minh khue", "nguyen thi hanh khue", "nguyen thi bich khue", "nguyen thi minh hue", "nguyen thi minh khu", "nguyen thi minh khoe"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("nguyen can tinh thue") OR ("nguyen can trinh thuc"))) or ("nguyen thi minh khue"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("nguyen can tinh thue") OR ("nguyen can trinh thuc"))) OR ("nguyen thi minh khue"))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"nguyen can tinh thue\") OR (\"nguyen can trinh thuc\"))) or (\"nguyen thi minh khue\"))*".
• Removing quotes may allow a broader search: (((( nguyen can tinh thue ) OR ( nguyen can trinh thuc ))) or ( nguyen thi minh khue ))*.