Perhaps you should try some spelling variations:
"trac cong vinh snippets" » "tran cong vinh snippets", "tra cong vinh snippets", "trao cong vinh snippets", "trac cong trinh snippets", "trac trong vinh snippets", "trac cong viec snippets", "trac cong vinh slippers"
"dung java java snippets" » "dung va java snippets", "dung java java slippers"
"locating bug code snippets" » "locating bug code slippers", "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: (((("trac cong vinh snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("trac cong vinh snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( trac cong vinh snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("trac cong vinh snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.