Perhaps you should try some spelling variations:
"nato science theories a:, life sciences" » "nato science theory a:, life sciences", "national science theories a:, life sciences"
"radio science three a:, life sciences" » "radio science thin a:, life sciences", "radio science third a:, life sciences"

Try widening your search to All Fields.

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 theories a:, life sciences") OR ("radio science three a:, life sciences")).
• Removing quotes may allow a broader search: (( nato science theories a:, life sciences ) or ( radio science three a:, life sciences )).
• Adding a wildcard symbol may retrieve word variants: (("nato science theories a:, life sciences") or ("radio science three a:, life sciences"))*.