Perhaps you should try some spelling variations:
"duong duc hoan snippets" » "luong duc hoan snippets", "duong qua hoan snippets", "dang duc hoan snippets", "duong duc hoang snippets", "duong duc hoa snippets", "duong duc toan 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 duc hoan 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 duc hoan snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( duong duc hoan snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("duong duc hoan snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.