Perhaps you should try some spelling variations:
"trong khoa co snippets" » "truong khoa co snippets", "tuong khoa co snippets", "trung khoa co snippets", "trong hoa co snippets", "trong khoa cong snippets", "trong khoa hoc 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: (((("trong khoa co snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("trong khoa co snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( trong khoa co snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("trong khoa co snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.