$re = '/<td.*?<a.*? title\s*=\s*"([^"]+).*?</td>/m';
$str = '<td><a href="/wiki/Wal-Mart_Stores,_Inc." title="Wal-Mart Stores, Inc."class="mw-redirect">Wal-Mart Stores, Inc.</a></td>
<td style="background: #ffffcc;"><a href="/wiki/Sinopec_Group" title="Sinopec Group" class="mw-redirect">Sinopec Group</a></td>';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php