Regex reg = new Regex(@"(?<=[:：""][\s\t]*)[^\n"";;\s]+(?=[\s\t]*[;"";\n])");
            string input = @"Content-Type： application/msword;
  name=""readme.doc""
Content-Transfer-Encoding： base64
Content-Disposition： attachment;
  filename="" readme.doc """;
            foreach (Match m in reg.Matches(input))
                Console.WriteLine(m.Value);

//print
application/msword
readme.doc
base64
attachment
readme.doc