Perhaps you should try some spelling variations:
"doanh hieu cac snippets" » "doanh sieu cac snippets", "doan dieu cac snippets", "dong hieu cac snippets", "doanh hieu luc snippets", "doanh hieu va snippets", "doanh hieu van 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: (((("doanh hieu 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: (((("doanh hieu cac snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( doanh hieu cac snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("doanh hieu cac snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.