Perhaps you should try some spelling variations:
"dung cu code snippets" » "dung cfd code snippets", "dung cua code snippets", "dung co code snippets", "dung cho code snippets", "dung cu 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 cu 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 cu code snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( giao trinh java snippets ) or ( dung cu code snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("giao trinh java snippets") or ("dung cu code snippets"))) or ("locating bug code snippets"))*.