Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"ket van toan snippets" » "ket van tuan snippets", "ket van tan snippets", "ket van thanh snippets", "ket va toan snippets", "viet van toan snippets", "ket doan 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: (((("ket 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: (((("ket van toan snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( ket van toan snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("ket van toan snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.