Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets", "python using java slippers"
"van hoc sinh snippets" » "van hoa sinh snippets", "van hoc dinh snippets", "van hoc minh snippets", "van hoc kinh snippets", "van hoc sinh slippers"
"locating bug code snippets" » "locating bug code slippers", "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 hoc sinh 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 hoc sinh snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( van hoc sinh snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("van hoc sinh snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.