Perhaps you should try some spelling variations:
"radio science theories a:, life sciences" » "radio science theory a:, life sciences", "radio science three a:, life sciences"
"national science theories a:, life sciences" » "national science theory a:, life sciences", "national science three a:, life sciences", "natural science theories a:, life sciences", "spatial science theories a:, life sciences", "animal science theories a:, life sciences"

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"radio science theories a:, life sciences\") OR (\"national science theories a:, life sciences\"))".
• Removing quotes may allow a broader search: (( radio science theories a:, life sciences ) OR ( national science theories a:, life sciences )).
• Adding a wildcard symbol may retrieve word variants: (("radio science theories a:, life sciences") OR ("national science theories a:, life sciences"))*.