Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"den hieu voi snippets" » "de hieu voi snippets", "den hien voi snippets", "ten hieu voi snippets", "den hieu moi snippets", "den lieu voi snippets", "den hieu loi 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: (((("den hieu voi snippets") or ("python using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("den hieu voi snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( den hieu voi snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("den hieu voi snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.