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