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