Perhaps you should try some spelling variations:
"nang vien cac snippets" » "nang viet cac snippets", "nang mien cac snippets", "giang vien cac snippets", "nang vien bach snippets", "nang vien dai snippets", "nang vien da 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: (((("nang vien cac snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("nang vien cac snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( nang vien cac snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("nang vien cac snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.