Perhaps you should try some spelling variations:
"cuon sach toc snippets" » "duong sach toc snippets", "cuoc cach toc snippets", "co sach toc snippets", "cuon bach tuoc snippets", "cuon sach duoc snippets", "cuon sach nuoc 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: (((("cuon sach toc snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("cuon sach toc snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( cuon sach toc snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("cuon sach toc snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.