Perhaps you should try some spelling variations:
"using java code snippets" » "using data code snippets"
"sach trinh duc snippets" » "sach tranh duc snippets", "hanh trinh duc snippets", "sach kinh duc snippets", "sach tinh duc snippets", "sach trinh doc snippets", "sach trinh dung snippets"
"locating bug core snippets" » "locating bug code snippets"

Try widening your search to All Fields.

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• Performing a fuzzy search may retrieve terms with similar spellings: (((("using java code snippets") or ("sach trinh duc snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("using java code snippets") OR ("sach trinh duc snippets"))) OR ("locating bug core snippets")).
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