Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"van thi hong snippets" » "van thi cong snippets", "van thi phuong snippets", "van thi hanh snippets", "van tai hong snippets", "dan thi hong snippets", "van thu hong 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 thi hong 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 thi hong snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( van thi hong snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("van thi hong snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.