Perhaps you should try some spelling variations:
"cong vang toan snippets" » "cong vang code snippets", "cong lang toan snippets", "cong quang toan snippets", "cong ngang toan snippets", "cong van toan snippets", "cong dang toan snippets", "cong vang trang 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 vang 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 vang toan snippets") OR ("dung java java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( cong vang toan snippets ) or ( dung java java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("cong vang toan snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))*.