Perhaps you should try some spelling variations:
"dang tran doan snippets" » "dang tran code snippets", "dang thanh doan snippets", "quang tran doan snippets", "hoang tran doan snippets", "dang trang doan snippets", "dang tan doan snippets", "dang tran hoan snippets"
"locating bug core snippets" » "locating bug code snippets"
"dung java java snippets" » "dung va java 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: (((("dang tran doan snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dang tran doan snippets") OR ("dung java java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( dang tran doan snippets ) or ( dung java java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dang tran doan snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))*.