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