Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"van van toan snippets" » "van van tuan snippets", "van van tan snippets", "van van thanh snippets", "van ban toan snippets", "tan van toan snippets", "san van toan 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: (((("van van toan snippets") or ("python using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("van van toan snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( van van toan snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("van van toan snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.