Perhaps you should try some spelling variations:
"dung khach hoc snippets" » "dung khang hoc snippets", "dung sach hoc snippets", "dung thanh hoc snippets", "dung khanh hoa snippets", "dung cach hoc snippets", "dung mach 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 khach 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 khach hoc snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung khach hoc snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung khach hoc snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.