It depends on what you are copying...
1)Text & Draft Entities can be copied between drawing using the Edit-Copy and Edit-Paste functionality.
2)Drawing view are not so easy, since they are asscociated to a model. You can use Insert-->Shared Data-->From File, but that would bring the whole drawing in, model associativity and all. (This works rather well when I have other people detailing individual parts for me, and I eventually have to bring it all into a master drawing).
Alternatively, you can select the view, hit Edit-->Convert to Draft Entities. This will turn your drawing view into simple lines (not associated to anything). This can then be copied as per 1) above.