$q=mysql_query("SELECT id,ad,link,aciklama FROM biyografi order by id DESC LIMIT 0,10");
while ($r=mysql_fetch_array($q)) {

<?php
$aciklama = $r[id];
if(empty($aciklama)) {
?>
<?=$r[ad];?>
<?php
} else {
?>
   <a href="biyografiler.php?id=<?=$r[id];?>"><?=$r[ad];?></a> 
<?php
}
?>