Admin facet jquery shouldn’t be loaded

I need to use jquery in my admin facet programming but it surely appears there isn’t any jquery loaded within the web page in any respect and it load solely at foremost web site! Has my wordpress any drawback which may’t load jquery or I ought to do one thing further to do it. Nevertheless I put this code in operate.php, but it surely not works:

if(is_admin()){        
    operate load_admin_script(){
        wp_enqueue_script('jquery_script', "/wp-includes/js/jquery/jquery.js");
    }
    add_action('admin_enqueue_scripts','load_admin_script');

 }