Perhaps you should try some spelling variations:
"luan nang cac snippets" » "luan van cac snippets", "van nang cac snippets", "luan san cac snippets", "luan nang cao snippets", "luan bang cac snippets", "luan hang cac 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 nang cac 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 nang cac snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( luan nang cac snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("luan nang cac snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.