Perhaps you should try some spelling variations:
"dung java java snippets" » "dung va java snippets"
"phan van cong snippets" » "pham van cong snippets", "thanh van cong snippets", "luan van cong snippets", "phan van dong snippets", "phan van phong snippets", "phan phan cong 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: (((("dung java java snippets") or ("phan van cong snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dung java java snippets") OR ("phan van cong snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung java java snippets ) or ( phan van cong snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung java java snippets") or ("phan van cong snippets"))) or ("locating bug code snippets"))*.