Perhaps you should try some spelling variations:
"dung viet van slippers" » "nang viet van slippers", "cong viet van slippers", "mang viet van slippers", "dung viet nam slippers", "dung viet anh slippers", "dung viet ha slippers", "dung viet van slippery", "dung viet van 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 viet van 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 viet van slippers") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung viet van slippers ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung viet van slippers") or ("dung java java snippets"))) or ("locating bug code snippets"))*.