Perhaps you should try some spelling variations:
"dung doanh hoc snippets" » "dung dan hoc snippets", "dung dong hoc snippets", "dung danh hoc snippets", "dung doanh khoa snippets", "dung doanh hoan snippets"
"dang java java snippets" » "dang 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: (((("dang java java snippets") or ("dung doanh hoc snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dang java java snippets") OR ("dung doanh hoc snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dang java java snippets ) or ( dung doanh hoc snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dang java java snippets") or ("dung doanh hoc snippets"))) or ("locating bug code snippets"))*.