Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets", "python using java slippers"
"duc tan 2019 snippets" » "duc ban 2019 snippets", "duc toan 2015 snippets", "duc nam 2019 snippets", "duc tan 2019 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: (((("duc tan 2019 snippets") or ("python using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("duc tan 2019 snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( duc tan 2019 snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("duc tan 2019 snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.