Perhaps you should try some spelling variations:
"trinh phap luan snippets" » "trinh phan luan snippets", "trinh han luan snippets", "trinh chat luan snippets", "trinh phap luat snippets", "trinh phap hoan snippets"
"dung java java slippers" » "dung va java slippers", "dung java java slippery", "dung java java grippers"
"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: (((("dung java java slippers") or ("trinh phap luan snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dung java java slippers") OR ("trinh phap luan snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung java java slippers ) or ( trinh phap luan snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung java java slippers") or ("trinh phap luan snippets"))) or ("locating bug code snippets"))*.