Perhaps you should try some spelling variations:
"cong trinh code snippets" » "cong trinh cong snippets", "cong trinh co snippets", "cong trinh cad snippets", "cong trinh code slippers"
"dung luan code snippets" » "dung luan cong snippets", "dung luan che snippets", "dung luan de snippets", "dung luan 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: (((("cong trinh code snippets") or ("dung luan code snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("cong trinh code snippets") OR ("dung luan code snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( cong trinh code snippets ) or ( dung luan code snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("cong trinh code snippets") or ("dung luan code snippets"))) or ("locating bug code snippets"))*.