Perhaps you should try some spelling variations:
"trinh van da snippets" » "trinh han da snippets", "trinh quan da snippets", "trinh toan da snippets", "trinh van dao snippets", "trinh van dau snippets", "trinh van dan snippets"
"dung java java snippets" » "dung va java snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code snippets", "locating bug core 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 da snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("trinh van da snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( trinh van da snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("trinh van da snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.