Courses roll from term to term (Fall to Fall, Spring to Spring, Summer to Summer). When this roll over occurs, it only shows courses that were offered that previous term. This means, there may be courses that have been approved through curriculum* that do not show the list of courses.
To show all courses that have been approved through curriculum, click the box next to Show courses with no sections underneath the red boxes on the upper right corner of the screen.
After checking the box, it should show the rest of the courses in the list.
*Note that new changes in curriculum are not instantly loaded into CLSS. Curriculum can be viewed online at https://nextcatalog.unl.edu/courseadmin/.