Perhaps you should try some spelling variations:
"using java code snippets" » "using data code snippets"
"dung viet long snippets" » "nang viet long snippets", "cong viet long snippets", "mang viet long snippets", "dung viet dong snippets", "dung viet song snippets", "dung viet huong 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 ("dung viet long snippets"))) or ("locating bug core snippets"))~.
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