I can't tell for Word 2013, but Word 2007 and 2010 did not provide any fields for including the DOI. So it is normal that the styles can't display them either.
Note that it is possible to extend Word to include those extra fields, but this results in invalid XML according to the schema. It works because the software doesn't care about the validity of the XML, but it is not something I would advise to do. If you still want to do it, just search this discussions list as there is some info on how to do it.
Note that it is possible to extend Word to include those extra fields, but this results in invalid XML according to the schema. It works because the software doesn't care about the validity of the XML, but it is not something I would advise to do. If you still want to do it, just search this discussions list as there is some info on how to do it.