Perhaps you should try some spelling variations:
"thi viet code snippets" » "thi viet co snippets", "thi viet some snippets", "thi lien code snippets", "thi viet 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: (((("thi viet 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: (((("thi viet code snippets") OR ("dung luan code snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( thi viet code snippets ) or ( dung luan code snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("thi viet code snippets") or ("dung luan code snippets"))) or ("locating bug code snippets"))*.