Perhaps you should try some spelling variations:
"dung khang hoc snippets" » "dung thang hoc snippets", "quang khang hoc snippets", "dung nhan hoc snippets", "dung khung hoc snippets", "dung khang thuoc snippets", "dung thang nhoc 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 khang 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 khang hoc snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung khang hoc snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung khang hoc snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.