Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"van cong hoc snippets" » "van dong hoc snippets", "van phong hoc snippets", "phan cong hoc snippets", "van cong hoa snippets", "van cong coc 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: (((("van cong hoc snippets") or ("python using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("van cong hoc snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( van cong hoc snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("van cong hoc snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.