I can't filter list term under admin/content
admin/content page doesn't list taxonomy terms, it shows content nodes. Those options in the select list are actually Content Types you can filter by.

To view taxonomy terms, the link is admin/structure/taxonomy.

Anyway, in the remote case you do want to have better filtering options for nodes, I recommend the module Admin Views.

After enabling Admin Views module, you can go to /admin/structure/views/view/admin_views_node/edit to edit the view that's responsible for displaying the admin node list. Here you can add as many exposed filters you need, in your case, the term reference field.

Admin Views also requires Views Bulk Operations module which allows you to execute operations on multiple nodes at once.

Edit: Your taxonomy vocabulary filter needs to be exposed to appear in the form (click on the filter, then click on 'Expose this filter to visitors, to allow them to change it'). Then all vocabularies should appear in the filter form.