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