Perhaps you should try some spelling variations:
"cong toan he snippets" » "cong tan he snippets", "cong hoan he snippets", "cong tuan he snippets", "cong toan ho snippets", "cong toan ke snippets", "cong toan ve 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 toan he 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 toan he snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( cong toan he snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("cong toan he snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.