Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"den hieu moi snippets" » "de hieu moi snippets", "den hien moi snippets", "ten hieu moi snippets", "den nhiem moi snippets", "den hieu so snippets", "den hieu bo 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 moi 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 moi snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( den hieu moi snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("den hieu moi snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.