Perhaps you should try some spelling variations:
"python missing data snippets" » "python using data snippets"
"locating bug core snippets" » "locating bug code snippets"
"do voi dan snippets" » "do hoi dan snippets", "do voi can snippets", "do doi dan snippets", "doi voi dan snippets", "dao voi dan snippets", "do moi dan 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: (((("do voi dan snippets") or ("python missing data snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("do voi dan snippets") OR ("python missing data snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( do voi dan snippets ) or ( python missing data snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("do voi dan snippets") or ("python missing data snippets"))) or ("locating bug core snippets"))*.