<ul class="grid">
    <?php
        while($row = mysql_fetch_array($result))
        {
        echo '<li>
         <p class="a">
            <p class="title-readMoreArtcile"><a href="dreje.php?id='.$row['id'].'">'.$row['serderr'].'</a></p>   
            <!-- <div class="date_main_hawpol">'.$row['Barwar'].'</div>-->
            <div class="body_hawpol">
               <!--'.snuri_wesha($row['nawerrok'], 14).' -->
                <img src="up/'.$row['wene'].'"          alt="'.$row['serderr'].'">
            </div>
        </p>
        </li>';
    
        }
    ?>
 </ul>

.grid li{
  float: right;
  width: 300px;
  overflow-x:hidden; 
}

<ul>
    <?php
        while($row = mysql_fetch_array($result))
        {
        echo ' <p class="a">
        
        <p class="title-readMoreArtcile"><a href="dreje.php?id='.$row['id'].'">'.$row['serderr'].'</a>
        </p>   
    <!--
    <div class="date_main_hawpol">'.$row['Barwar'].'
        </div>
        -->
      <div class="body_hawpol">
       <!--'.snuri_wesha($row['nawerrok'], 14).' -->
               <img src="up/'.$row['wene'].'"          alt="'.$row['serderr'].'">

    </div>
    </p>';
    
        }
    ?>
    </ul>