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