Perhaps you should try some spelling variations:
"dung viec chi snippets" » "dung viet chi snippets", "dung vien chi snippets", "nhung viec chi snippets", "dung viec cho snippets", "dung viec cuoi snippets", "dung viec phai 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 viec chi 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 viec chi snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung viec chi snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung viec chi snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.