Perhaps you should try some spelling variations:
"tong luan cac snippets" » "tang luan cac snippets", "dung luan cac snippets", "hang luan cac snippets", "tong luan dac snippets", "tong luan tac snippets", "tong luat cac 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: (((("tong luan 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: (((("tong luan cac snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( tong luan cac snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("tong luan cac snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.