Angular: Explain why URL is lost on page reload?

Question

JavaScript

I made Angular without "#" and "#!", but for some reason, during a normal (to Ajax) transition to the page or update, the URL is lost (It gets back to the main one). I can't understand it...
After all, vk.com doesn't lose its url when the page is reloaded.
With tags "#" and "#!" it didn't happen.
Firefox 35 Linux Gentoo

app.config(function($routeProvider, $locationProvider){
    $locationProvider.html5Mode(true);
    $locationProvider.hashPrefix('!');
    $routeProvider.when('/',{
        templateUrl:"partials/list.html",
        controller:"SiteCtrl"
    })
    .when('/article/:article', {
        templateUrl:"partials/post.html",
        controller:"SiteCtrl"
    })
    .when('/category/:category', {
        templateUrl:"partials/category_post.html",
        controller:"SiteCtrl"
    })
    .when('/event-category/:category', {
        templateUrl:"partials/category_event.html",
        controller:"SiteCtrl"
    })
    .when('/event/:event', {
        templateUrl:"partials/event.html",
        controller:"SiteCtrl"
    })
    .when('/events', {
        templateUrl:"partials/events.html",
        controller:"SiteCtrl"
    })
    .when('/pictures',{
        templateUrl:"partials/pictures.html",
        controller:"SiteCtrl"
    })
    .when('/calendar',{
        templateUrl:"partials/calendar.html",
        controller:"SiteCtrl"
    })
    .when('/page/:slug', {
        templateUrl:"partials/page.html",
        controller:"SiteCtrl"
    })
    .otherwise({
        redirectTo:'/'
    });