Perhaps you should try some spelling variations:
"dung minh toan snippets" » "dung minh code snippets", "duong minh toan snippets", "dung ninh toan snippets", "dung vinh toan snippets", "dung tinh toan snippets", "dung manh toan snippets", "dung minh tuan snippets"
"locating bug core snippets" » "locating bug code snippets"
"dung java java snippets" » "dung va java 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 minh toan snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dung minh toan snippets") OR ("dung java java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( dung minh toan snippets ) or ( dung java java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung minh toan snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))*.