Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"sach tet cao snippets" » "sach tien cao snippets", "sach tren cao snippets", "sach viet cao snippets", "sach te cao snippets", "sach tet co 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 tet cao 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 tet cao snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( sach tet cao snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("sach tet cao snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.