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