Perhaps you should try some spelling variations:
"dung danh muc slippers" » "dung doanh muc slippers", "dung dan muc slippers", "dung dang muc slippers", "dung danh tu slippers", "dung danh muc slippery", "dung danh muc grippers"
"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: (((("dung danh muc slippers") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dung danh muc slippers") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung danh muc slippers ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung danh muc slippers") or ("dung java java snippets"))) or ("locating bug code snippets"))*.