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