Perhaps you should try some spelling variations:
"dung viet doan snippets" » "dung viet hoan snippets", "dung viet hoang snippets", "dung viet van snippets", "nang viet doan snippets", "cong viet doan snippets", "mang viet doan snippets"
"using a code snippets" » "using a core snippets"
"locating bug code snippets" » "locating bug core snippets", "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: (((("using a code snippets") or ("dung viet doan snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("using a code snippets") OR ("dung viet doan snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( using a code snippets ) or ( dung viet doan snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("using a code snippets") or ("dung viet doan snippets"))) or ("locating bug code snippets"))*.