Perhaps you should try some spelling variations:
"duong tuan do snippets" » "duong quan do snippets", "duong xuan do snippets", "duong tan do snippets", "duong toan do snippets", "duong truan doi snippets", "duong quan doi snippets"
"dung java java snippets" » "dung va java 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: (((("duong tuan do snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("duong tuan do snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( duong tuan do snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("duong tuan do snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.