I think the reason may be that you didn't load the related JS file and CSS style.
Here is a demo for your reference:
<!DOCTYPE html>
<html>
<head>
<title>jQuery bootstrap-select</title>
<script type="text/javascript" src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.8.3.min.js"></script>
<script type="text/javascript" src="http://cdn.bootcss.com/bootstrap-select/2.0.0-beta1/js/bootstrap-select.js"></script>
<link rel="stylesheet" type="text/css" href="http://cdn.bootcss.com/bootstrap-select/2.0.0-beta1/css/bootstrap-select.css">
<!-- 3.0 -->
<link href="http://netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" rel="stylesheet">
<script src="http://netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<!-- 2.3.2
<link href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.min.css" rel="stylesheet">
<script src="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/js/bootstrap.js"></script>
-->
</head>
<body>
<div class="container">
<ul class="nav nav-pills nav-stacked col-md-2">
<li class="active"><a href="#tab_a" data-toggle="pill">Pill A</a></li>
<li><a href="#tab_b" data-toggle="pill">Pill B</a></li>
<li><a href="#tab_c" data-toggle="pill">Pill C</a></li>
<li><a href="#tab_d" data-toggle="pill">Pill D</a></li>
</ul>
<div class="tab-content col-md-10">
<div class="tab-pane active" id="tab_a">
<h4>Pane A</h4>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa.</p>
</div>
<div class="tab-pane" id="tab_b">
<h4>Pane B</h4>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa.</p>
</div>
<div class="tab-pane" id="tab_c">
<h4>Pane C</h4>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa.</p>
</div>
<div class="tab-pane" id="tab_d">
<h4>Pane D</h4>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa.</p>
</div>
</div><!-- tab content -->
</div>
</body>
</html>
Screenshot of result:

jqueryandbootstrap? Are there any console errors ?