string source = @"www.icbc.com.cn || www.baidu.com || www.sina.cn || www.csdn.net";
            Regex reg = new Regex(@"www.(?<name>\w*\W*).(com|cn|net)");
            Match mm = reg.Match(source);
            MatchCollection mc = reg.Matches(source);
            foreach (Match m in mc)
            {
                MessageBox.Show(m.Groups["name"].Value);
            }