Perhaps you should try some spelling variations:
"locating bug core snippets" » "locating bug code snippets"
"python using java snippets" » "python using data snippets"
"sach thi dan snippets" » "sach thu dan snippets", "sach tai dan snippets", "sach thieu dan snippets", "sach thi doan snippets", "sach thi lan snippets", "sach thi dai 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 thi dan snippets") or ("python using java snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("sach thi dan snippets") OR ("python using java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( sach thi dan snippets ) or ( python using java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("sach thi dan snippets") or ("python using java snippets"))) or ("locating bug core snippets"))*.