Perhaps you should try some spelling variations:
"luan khoa de snippets" » "khuan khoa de snippets", "toan khoa de snippets", "luan hoan de snippets", "luan khoa dr snippets", "luan khoa he snippets", "luan khoi de 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: (((("luan khoa de snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("luan khoa de snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( luan khoa de snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("luan khoa de snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.