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