string(248) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%BA%A2%E6%9D%89%E8%B5%84%E6%9C%AC%E6%8A%95%E8%B5%84%E4%BA%86%E5%93%AA%E4%BA%9B%E5%85%AC%E5%8F%B8 => Received HTTP code 403 from proxy after CONNECT"
红杉资本投资了哪些公司
