Perhaps you should try some spelling variations:
"cong tuan du snippets" » "cong tan du snippets", "cong luan du snippets", "cong thanh du snippets", "cong toan du snippets", "cong xuan du snippets", "cong tuan cu 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: (((("cong tuan du snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("cong tuan du snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( cong tuan du snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("cong tuan du snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.