Perhaps you should try some spelling variations:
"duong xuan cao snippets" » "dong xuan cao snippets", "luong xuan cao snippets", "duong quan cao snippets", "duong xuan can snippets", "duong juan cao snippets", "duong xuan bao 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: (((("duong xuan cao snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("duong xuan cao snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( duong xuan cao snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("duong xuan cao snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.