Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"doc van cong snippets" » "doc van dong snippets", "doc van phong snippets", "doc phan cong snippets", "do van cong snippets", "hoc van cong snippets", "duc 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: (((("doc 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: (((("doc van cong snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( doc van cong snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("doc van cong snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.