Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"thpt dan hoc snippets" » "thuc dan hoc snippets", "tho dan hoc snippets", "thpt van hoc snippets", "thpt dan toc snippets", "thpt dai hoc 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: (((("thpt dan 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: (((("thpt dan hoc snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( thpt dan hoc snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("thpt dan hoc snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.