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