Perhaps you should try some spelling variations:
"va duong luan snippets" » "va dung luan snippets", "va dong luan snippets", "va duong quan snippets", "van duong luan snippets", "va tuong luan snippets", "va huong luan snippets", "va duong luan slippers"
"python using sat snippets" » "python using data snippets", "python using a snippets", "python using raw snippets", "python using sat 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.

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• Performing a fuzzy search may retrieve terms with similar spellings: (((("va duong luan snippets") or ("python using sat snippets"))) or ("locating bug code snippets"))~.
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