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