Perhaps you should try some spelling variations:
national science » natural science, spatial science, animal science
medical sciences » social sciences
science series » science services, science stories, science theories

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: national science series c:, mathematical AND medical sciences.
• Adding a wildcard symbol may retrieve word variants: national science series c:, mathematical and medical sciences*.