Problem with inclusion of Javascript from Plugin

Hello everybody, I’m newbie of WordPress.
I want include in the theme header some javascript necessary to work for my plugin.

It’s possible do it only in theme header?

I add this code:
wp_enqueue_script(“jquery”);
wp_enqueue_script(“jquery-ui-core”);
wp_enqueue_script(“jquery-ui-dialog”);
wp_enqueue_script( ‘wp-timetracking’, plugins_url(‘/wp-timetracking/js/fullcalendar/fullcalendar.js’), array( ‘jquery’ ) );

and I have all in my theme.

But if I moved this code in my plugin javascripts aren’t load. Anybody have the solution.

Thanks