Perhaps you should try some spelling variations:
"nato science theories b:, physics" » "nato science theory b:, physics", "nato science three b:, physics", "radio science theories b:, physics", "nato science theories 3:, physics", "nato science theories 1:, physics", "nato science theories 2:, physics"
"nato science theories 4:, physics" » "nato science theory 4:, physics", "nato science three 4:, physics", "radio science theories 4:, physics", "nato science theories 3:, physics"
"national science theories b:, physics" » "national science theory b:, physics", "national science three b:, physics", "natural science theories b:, physics", "spatial science theories b:, physics", "animal science theories b:, physics", "national science theories 3:, physics", "national science theories 1:, physics", "national science theories 2:, physics"

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 b:, physics") OR ("nato science theories 4:, physics"))) OR ("national science theories b:, physics")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"nato science theories b:, physics\") OR (\"nato science theories 4:, physics\"))) or (\"national science theories b:, physics\"))".
• Removing quotes may allow a broader search: (((( nato science theories b:, physics ) OR ( nato science theories 4:, physics ))) or ( national science theories b:, physics )).
• Adding a wildcard symbol may retrieve word variants: (((("nato science theories b:, physics") OR ("nato science theories 4:, physics"))) or ("national science theories b:, physics"))*.