Perhaps you should try some spelling variations:
"dung vinh hoc snippets" » "dang vinh hoc snippets", "dung ninh hoc snippets", "quang vinh hoc snippets", "dung sinh hoc snippets", "dung hinh hoc snippets", "dung tinh hoc 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 vinh hoc 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 vinh hoc snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung vinh hoc snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung vinh hoc snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.