$re = '/(?<=Hyperlink" href=")((http)(.+?)(\"|\').*?)/m';
$str = '<td style="vertical-align: top; width: 375px"><h1 id="H_67e23f29-bb69-46eb-b15c">00 - <a class="Hyperlink" href="http://xxxx.xxxxxxx.com/Management/HyperlinkLoader.aspx?HyperlinkID=c64b7052-4229-4169-b8a2" class="Hyperlink" onmouseover="HyperlinkLoader.showTooltip(event,\'c64b7052-4229-4169-b8a2\')" onclick="HyperlinkLoader.followHyperlink(event,{\'HyperlinkID\':\'c64b7052-4229-4169-b8a2\',\'ReturnURL\':\'\'});return false">Algemeen</a></h1></td>
<td style="width: 292px; vertical-align: top; background-color: rgb(255, 255, 255); text-align: left"><a class="Hyperlink" href="http://xxxx.xxxxxxx.com/Management/HyperlinkLoader.aspx?HyperlinkID=29517117-26ce-4004-88ed" class="Hyperlink" onmouseover="HyperlinkLoader.showTooltip(event,\'29517117-26ce-4004-88ed\')" onclick="HyperlinkLoader.followHyperlink(event,{\'HyperlinkID\':\'29517117-26ce-4004-88ed\',\'ReturnURL\':\'\'});return false">Asbestbeheersplan</a></td>
<td style="vertical-align: top; width: 375px"><h1 id="H_f534b7b2-a8f5-41b0-9aa8">01 - <a class="Hyperlink" href="http://xxxx.xxxxxxx.com/Management/HyperlinkLoader.aspx?HyperlinkID=7af55197-d865-4cb2-bb9c" class="Hyperlink" onmouseover="HyperlinkLoader.showTooltip(event,\'7af55197-d865-4cb2-bb9c\')" onclick="HyperlinkLoader.followHyperlink(event,{\'HyperlinkID\':\'7af55197-d865-4cb2-bb9c\',\'ReturnURL\':\'\'});return false">Voor werken geldende voorwaarden</a></h1></td>';
preg_match_all($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