Perhaps you should try some spelling variations:
"dung tren cong snippets" » "dung trong cong snippets", "dung trung cong snippets", "dung trien cong snippets", "dung tien cong snippets", "dung tran cong 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 tren cong 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 tren cong snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung tren cong snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung tren cong snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.