Perhaps you should try some spelling variations:
"national science series 10:, physics" » "natural science series 10:, physics", "spatial science series 10:, physics", "animal science series 10:, physics", "national science services 10:, physics", "national science stories 10:, physics", "national science theories 10:, physics", "national science series 3:, physics", "national science series 2:, physics", "national science series 30:, physics", "national science series 20:, physics"
"nato science series 20:, physics" » "nato science services 20:, physics", "nato science stories 20:, physics", "nato science theories 20:, physics", "radio science series 20:, physics", "nato science series 2:, physics", "nato science series 23:, physics", "nato science series 21:, physics"
"nato science series 1:, physics" » "nato science services 1:, physics", "nato science stories 1:, physics", "nato science theories 1:, physics", "radio science series 1:, physics", "nato science series 3:, physics", "nato science series 2:, physics"

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: (((("nato science series 20:, physics") OR ("nato science series 1:, physics"))) OR ("national science series 10:, physics")).
• Removing quotes may allow a broader search: (((( nato science series 20:, physics ) or ( nato science series 1:, physics ))) or ( national science series 10:, physics )).
• Adding a wildcard symbol may retrieve word variants: (((("nato science series 20:, physics") or ("nato science series 1:, physics"))) or ("national science series 10:, physics"))*.