If I am missing something about your question (which actually did not provide enough information to diagnose the problem that you actually have), this is required owl:imports. You can import other (OWL) ontologies into your own. In Protégé, you simply use the Ontology import on the Active Ontology tab to specify the ontologies you want to import.

Remember that Protégé is an OWL tool, so if you are importing something with this function, it should also be an OWL ontology. You will have mixed luck if you try to import RDF (S) dictionaries. For example, you can get properties, but as properties of annotations, not properties of an object and data type.
There are several related questions and answers at answer.semanticweb.com: