Perhaps you should try some spelling variations:
"luan tranh doc snippets" » "luan thanh doc snippets", "lan tranh doc snippets", "quan thanh doc snippets", "luan tranh duoc snippets", "luan trinh doc snippets", "luan tranh cuoc 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: (((("luan tranh doc snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("luan tranh doc snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( luan tranh doc snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("luan tranh doc snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.