//搜索关键词    
        private function searchCas($cas){
            Log::info('searchCas', [$cas]);
            $url = "http://www.bbssff.com/m/search";
            try{
                $client = new Client();
                $response = $client->post($url,[
                    'form_params'=>[
                         'cas-search'=>$cas
                    ],
                    'allow_redirects' => true
                ]);
                $html = $response->getBody();
                Log::info('html ', [$html]);
            }catch (Exception $e){
                Log::info('searchCasException ', [$e]);
                return false;
            }
            $dom = new \DOMDocument();
            @$dom->loadHTML($html);
            $dom->normalize();
            $xpath = new \DOMXPath($dom);
            //$hrefs = $xpath->query('/html/body//a[@class="checkmore"]//@href');
            $hrefs = $xpath->query('/html/body//a[text()="化学百科"]//@href');
            $link = '';
            if($hrefs->length == 0){
                return false;
            }
            if($hrefs->length >= 1){
                $href = $hrefs->item(0);
                $link = $href->nodeValue;
            }
            //判断链接是否合法
            if(strpos($link, '-d') === false){
                return false;
            }
            $url = 'http://www.bbssy.com'.$link;
            $content = $this->spiderDetail($url);
            if(!$content) false;
            ProdContent::create(array(
                 'cas'=>$cas,
                 'url'=>$url,
                 'content'=>$content
            ));
            //更新prod 抓取状态
            Prod::where('cas','=',$cas)->update(
                 array(
                     'is_guzzle'=>1
                 )
            );
            return true;
           /* for ($i = 0; $i < $hrefs->length; $i++) {
                $href = $hrefs->item($i);
                $linktext = $href->nodeValue;
                Log::info('href', [$linktext]);
            }*/
        }