Perhaps you should try some spelling variations:
"python missing data snippets" » "python using data snippets"
"locating bug core snippets" » "locating bug code snippets"
"hoa van va snippets" » "hoa dan va snippets", "hoang van va snippets", "hoa phan va snippets", "hoa van vat snippets", "hoa van van snippets", "hoa ban va snippets"

Try widening your search to All Fields.

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• Performing a fuzzy search may retrieve terms with similar spellings: (((("hoa van va snippets") or ("python missing data snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("hoa van va snippets") OR ("python missing data snippets"))) OR ("locating bug core snippets")).
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