Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"sach dac cho snippets" » "sach dao cho snippets", "sach dat cho snippets", "sach bac cho snippets", "sach day cho snippets", "sach danh cho 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: (((("sach dac cho snippets") or ("python using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("sach dac cho snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( sach dac cho snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("sach dac cho snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.