Perhaps you should try some spelling variations:
"nguyen chi dinh thi" » "nguyen nhu dinh thi", "nguyen hai dinh thi", "nguyen thu dinh thi", "nguyen chi minh thi", "nguyen chi binh thi", "nguyen chu dinh thi", "nguyen chi dinh tri"
"nguyen can minh chau" » "nguyen van minh chau", "nguyen xuan minh chau", "nguyen cong minh chau", "nguyen can tinh chat", "nguyen cao minh chau", "nguyen ban minh chau"
"nguyen thi dinh thi" » "nguyen thi dinh tri", "nguyen thoi dinh thi", "nguyen thi minh thi", "nguyen thi hinh thi"

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 dinh thi") OR ("nguyen thi dinh thi"))) or ("nguyen can minh chau"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("nguyen chi dinh thi") OR ("nguyen thi dinh thi"))) OR ("nguyen can minh chau"))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"nguyen chi dinh thi\") OR (\"nguyen thi dinh thi\"))) or (\"nguyen can minh chau\"))*".
• Removing quotes may allow a broader search: (((( nguyen chi dinh thi ) OR ( nguyen thi dinh thi ))) or ( nguyen can minh chau ))*.