Bootstrap在Laravel 5.2中的视图文件中不起作用

I'm a new user of Laravel 5.2. Laravel 5.2 uses bootstrap 3.3.6

I tried to add bootstrap tooltip in view files, but it doesn't work

when i test the script below, it shows that jquery doesn't work :

<script>
$(document).ready(function(){
    $('[data-toggle="tooltip"]').tooltip(); 
});
</script>

so I tested :

$(document).ready(function(){
    alert('hello'); 
});

also it didn't work! but when I test just:

alert('hello');

it works

at app.blade.php i have something like this:

<script src="{{URL::asset('assets/js/jquery.min.js')}}"></script>
<script src="{{URL::asset('assets/js/bootstrap.min.js')}}"></script>
{{-- <script src="{{ elixir('js/app.js') }}"></script> --}}

and at the head tag I have :

<link rel="stylesheet" href="{{ URL::asset('assets/css/bootstrap.min.css') }}">