$str=<<<STR
<div id="divPdf0" title="../2003Z/hb/z063.pdf#page=2" class="downpdf" style="cursor:hand;">1主题内容与适用范围</div>
<div id="divPdf1" title="../2003Z/hb/z063.pdf#page=2" class="downpdf" style="cursor:hand;">2原理</div>
<div id="divPdf2" title="../2003Z/hb/z063.pdf#page=2" class="downpdf" style="cursor:hand;">3试剂</div>
<div id="divPdf3" title="../2003Z/hb/z063.pdf#page=4" class="downpdf" style="cursor:hand;">4仪器、设备</div>
<div id="divPdf4" title="../2003Z/hb/z063.pdf#page=4" class="downpdf" style="cursor:hand;">5采样及样品保存</div>
STR;

preg_match('/<div.*?title="([^#"]+)/',$str,$matche);
echo $matche[1];

------解决方案--------------------
preg_match('/title="([^#\"]+)#/s',$s,$m);
prinit_r($m[1]);

------解决方案--------------------
/<img src="\/images\/(.*?)"/iUs

------解决方案--------------------
/<img src="\/images\/(.*)"/iUs     //这样呢？

------解决方案--------------------

 $contents = $match[1];
foreach($contents as &$v) $v='http://localhost/'.$v;
    $contents = implode('#',$contents);
   echo $contents;