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