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