Perhaps you should try some spelling variations:
"dung sach noi snippets" » "duong sach noi snippets", "dung sai noi snippets", "dung cac noi snippets", "dung cach noi snippets", "dung sach doi snippets", "dung sach hoi 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 sach noi 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 sach noi snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung sach noi snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung sach noi snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.