Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"ham dan toan snippets" » "ham van toan snippets", "ham dan than snippets", "ham manh toan snippets", "nam dan toan snippets", "hat dan toan snippets", "hai dan 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: (((("ham dan 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: (((("ham dan toan snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( ham dan toan snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("ham dan toan snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.