Perhaps you should try some spelling variations:
"nguyen chi minh khai" » "nguyen can minh khai", "nguyen nhu minh khai", "nguyen hai minh khai", "nguyen chi minh khue", "nguyen chi minh chau", "nguyen chi minh chi"
"nguyen thi minh khai" » "nguyen thi minh khue", "nguyen thi minh chau", "nguyen thi minh chi", "nguyen thi hanh khai", "nguyen thi bich khai"
"nguyen thi tinh chat" » "nguyen thai tinh chat", "nguyen thi trinh chat", "nguyen thi thinh chat", "nguyen thi tinh nhat", "nguyen thi tinh phat"

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