Perhaps you should try some spelling variations:
"nguyen chi minh khai" » "nguyen can minh khai", "nguyen nhu minh khai", "nguyen thu minh khai", "nguyen chi minh khue", "nguyen chi minh chau", "nguyen chi minh chi"
"nguyen hai tinh chat" » "nguyen van tinh chat", "nguyen huu tinh chat", "nguyen can tinh chat", "nguyen thai tinh chat", "nguyen nhai tinh chat", "nguyen chai tinh chat"
"nguyen thi minh khai" » "nguyen thi minh khue", "nguyen thi minh chau", "nguyen thi minh chi", "nguyen thi hanh khai", "nguyen thi bich khai"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("nguyen chi minh khai") or ("nguyen hai tinh chat"))) or ("nguyen thi minh khai"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("nguyen chi minh khai") OR ("nguyen hai tinh chat"))) OR ("nguyen thi minh khai")).
• Removing quotes may allow a broader search: (((( nguyen chi minh khai ) or ( nguyen hai tinh chat ))) or ( nguyen thi minh khai )).
• Adding a wildcard symbol may retrieve word variants: (((("nguyen chi minh khai") or ("nguyen hai tinh chat"))) or ("nguyen thi minh khai"))*.