请问个正则表达式

$s=<<<txt ","bdsourcename":"","bdfrompagetitleprefix":"","token":"8095"},{"thumburl":"http:="" t2.baidu.com="" it="" u="2984778172,1478112097&fm=0&gp=0.jpg","middleURL":"http://t2.baidu.com/it/u=2984778172,1478112097&fm=51&gp=0.jpg","largeTnImageUrl":"http://t2.baidu.com/it/u=2984778172,1478112097&fm=52&gp=0.jpg","hasLarge"" :="" 0,"pagenum":40,"objurl":"http:="" www.che51.com="" uploadfiles="" image="" gallery="" 2_pic_200912250127432009.jpg="" ","fromurl":"http:="" picture="" carinfo.aspx?car_id="1781&carserialsid=227" ","fromurlhost":"http:="" ","currentindex":"28638="" ","width":174,"height":121,"type":"jpg","filesize":"52","bdsrctype":"0","di":"64754191000","is":"0,0","bdsetimgnum":0,"bdimgnewsdate":"1970-01-01="" 08:00","frompagetitle":"新<strong="">bmw<\/strong> <strong>530li<\/strong>典雅型 ","bdSourceName":"","bdFromPageTitlePrefix":"","token":"9011"},{"thumbURL":"http://t3.baidu.com/it/u=167097252,823550504&fm=0&gp=0.jpg","middleURL":"http://t3.baidu.com/it/u=167097252,823550504&fm=51&gp=0.jpg","largeTnImageUrl":"http://t3.baidu.com/it/u=167097252,823550504&fm=52&gp=0.jpg","hasLarge" : 0,"pageNum":41,"objURL":"http://www.2sauto.net/db/upload/s_20081013200290.jpg "
txt;
preg_match_all('/"objURL":"(.+)"/sU',$s,$m);
print_r($m[1]);                     </strong></txt>