NCTM journals don't provide their most recent content online. You'll need the physical copy: most recent issues on Level 10 in the Current Serials Section. Older titles will be on level 9, and you will need the call # to access.
As you enter the teaching profession, it is important to recognize that the field is supported by a large body of professional and academic literature. Exploring current issues and trends in education is important, and there are quality, authoritative sources you can consult.