Perhaps you should try some spelling variations:
"mang viet cd snippets" » "nang viet cd snippets", "anh viet cd snippets", "mai viet cd snippets", "mang viet co snippets", "mang viet ca snippets", "mang viet cho snippets"
"dung java java snippets" » "dung va java snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code snippets", "locating bug core 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: (((("mang viet cd snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("mang viet cd snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( mang viet cd snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("mang viet cd snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.