Perhaps you should try some spelling variations:
"trinh luan dung snippets" » "trinh luat dung snippets", "trinh quan dung snippets", "trinh han dung snippets", "trinh lan dung snippets", "trinh luan dong snippets", "trinh luan hung 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 luan dung 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 luan dung snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung java java slippers ) or ( trinh luan dung snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung java java slippers") or ("trinh luan dung snippets"))) or ("locating bug code snippets"))*.