How to correctly include jquery-ui effects on wordpress

[admin]

I've been trying to include the jquery ui effects (more specifically the shake effect) on my wordpress theme. So far, I've only been able to include the jQuery script, but I really have no clue where to place the ui scripts and how to enqueue them.

This is the code I have. It obviously doesnt work:

    <?php wp_enqueue_script("jquery"); ?>
<?php wp_enqueue_script("jquery-ui-core"); ?>
<?php wp_head(); ?>
<link rel="stylesheet" type="text/css" href="<?php bloginfo('stylesheet_url'); ?>" />
<script type="text/javascript">
    var $j = jQuery.noConflict();
    $j(document).ready(function() {
        $j("#manita-imagen").mouseover(function(){
            //$j(this).animate({ opacity: "hide" })
            // alert('asd');
            $j(this).effect("shake", { times:3 }, 300);
        });
    });

 </script>

Thanks for your help!