Perhaps you should try some spelling variations:
"dung trinh luan snippets" » "dung tinh luan snippets", "dong trinh luan snippets", "cong trinh luan snippets", "dung trinh luat snippets", "dung trinh quan snippets", "dung trinh han snippets", "dung trinh luan slippers"
"dung cho code snippets" » "dung cho cong snippets", "dung cfd code snippets", "dung cho con snippets", "dung cho code slippers"
"locating bug code snippets" » "locating bug code slippers", "locating bung code snippets", "locating bugs code 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: (((("dung trinh luan snippets") or ("dung cho code snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dung trinh luan snippets") OR ("dung cho code snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung trinh luan snippets ) or ( dung cho code snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung trinh luan snippets") or ("dung cho code snippets"))) or ("locating bug code snippets"))*.