Perhaps you should try some spelling variations:
"dung xuan du snippets" » "duong xuan du snippets", "dung luan du snippets", "dung quan du snippets", "dung xuan duc snippets", "dung xuan huy snippets", "dung xuan thu 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: (((("dung xuan du snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dung xuan du snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung xuan du snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung xuan du snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.