private void button5_Click(object sender, EventArgs e)
        {
            string html = "";
            WebHeaderCollection header = new WebHeaderCollection();
            header.Set("Pragma", "no-cache");
            html = getHtml("http://www.biomart.cn/info/infoDemand.htm?pge=1",header);
            Regex regex = new Regex("<!-- 列表 -->(?<1>.*)<!-- /列表 -->");
            //MessageBox.Show(regex.Match(html).Groups.Count.ToString());
            html = regex.Match(html).Groups[1].Value;
            regex = new Regex("href=\"(?<1>http://www\\.biomart\\.cn/infodemand/\\w+\\.htm)\"");
            MatchCollection ms = regex.Matches(html);
            header.Set(HttpRequestHeader.Cookie, "__utma=124945049.1686326021.1305093063.1305164868.1305187067.3; __utmz=124945049.1305093063.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); JSESSIONID=9D7F7F4B5D73F453DA54B40A53D5E7C8; __utmc=124945049; __utmb=124945049.2.10.1305187067");
            foreach(Match m in  ms){
                MessageBox.Show(m.Groups[1].Value);
                String content = getHtml(m.Groups[1].Value,header);
                 regex = new Regex("<div class=\"product_card\">(?<1>.*)\\s+</p>\\s+</div>");
                 MessageBox.Show(regex.Match(content).Groups[1].Value);
            }
        } 

 
?private String getHtml(String url, WebHeaderCollection header)
        {
            WebHeaderCollection header = new WebHeaderCollection();
            header.Set("", "");
            header.Set(HttpRequestHeader.Cookie, "");
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://www.biomart.cn/info/infoDemand.htm?pge=1");
            request.Timeout = 30000;
            request.Headers = header;
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream stream = response.GetResponseStream();
            Encoding encoding = Encoding.GetEncoding("UTF-8");
            StreamReader reader = new StreamReader(stream);
            String content = reader.ReadToEnd();
            content = Regex.Replace(content, "\\t|\\r|\\n", "");
            return content;
        }