Perhaps you should try some spelling variations:
"doanh van code slippers" » "doan van code slippers", "doanh va code slippers", "doanh ban code slippers", "doanh van de slippers", "doanh van hoe slippers", "doanh van cong slippers"
"dung cong code snippets" » "dung trong code snippets", "dung cong cong snippets", "dung cong co snippets", "dung cong che snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code 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: (((("doanh van code slippers") or ("dung cong code snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("doanh van code slippers") OR ("dung cong code snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( doanh van code slippers ) or ( dung cong code snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("doanh van code slippers") or ("dung cong code snippets"))) or ("locating bug code snippets"))*.