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