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