JQuery - Uncaught TypeError: $(...).dialog is not a function

function crear_carpeta() {

    $("#crear").dialog({

        autoOpen: true,

        height: 500,

        minWidth: 910,

        maxWidth: 910,

        modal: true,

        show: "clip",

        hide: "clip"

    });

}

$("#crear").dialog({

<meta charset="utf-8" />

<meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no" />

<link rel="stylesheet" href="<?= $base_url ?>css/main.css" />

<link rel="stylesheet" href="<?= $base_url ?>css/jquery-ui.min.css" />

<script src="<?= $base_url ?>js/jquery.js"></script>

<script src="<?= $base_url ?>js/jquery-ui.min.js"></script>

<script src="<?= $base_url ?>js/jquery.min.js"></script>

<script src="<?= $base_url ?>js/browser.min.js"></script>

<script src="<?= $base_url ?>js/breakpoints.min.js"></script>

<script src="<?= $base_url ?>js/util.js"></script>

<script src="<?= $base_url ?>js/main.js"></script>

<script src="<?= $base_url ?>js/general.js"></script>