Perhaps you should try some spelling variations:
"dung viet toan snippets" » "dung viet code snippets", "nang viet toan snippets", "cong viet toan snippets", "mang viet toan snippets", "dung viet hoan snippets", "dung viet tran snippets", "dung viet tuan snippets"
"locating bug core snippets" » "locating bug code snippets"
"dung java java snippets" » "dung va java 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 java java snippets") or ("dung viet toan snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dung java java snippets") OR ("dung viet toan snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( dung java java snippets ) or ( dung viet toan snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung java java snippets") or ("dung viet toan snippets"))) or ("locating bug core snippets"))*.