Perhaps you should try some spelling variations:
"trinh van dat snippets" » "trinh han dat snippets", "trinh quan dat snippets", "trinh toan dat snippets", "trinh van dao snippets", "trinh van dau snippets", "trinh dan dat snippets", "trinh van dat slippers"
"dung cfd code snippets" » "dung cho code snippets", "dung cua code snippets", "dung co code snippets", "dung cfd code slippers", "dung cfd core snippets"
"locating bug code snippets" » "locating bug code slippers", "locating bug core snippets", "locating bung code snippets", "locating bugs code snippets"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("trinh van dat snippets") or ("dung cfd code snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("trinh van dat snippets") OR ("dung cfd code snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( trinh van dat snippets ) or ( dung cfd code snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("trinh van dat snippets") or ("dung cfd code snippets"))) or ("locating bug code snippets"))*.