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

Try widening your search to All Fields.

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• If you are trying to use Boolean operators, they must be ALL CAPS: (("nato science series 1:, physics") OR ((("nato science theories 1:, physics") OR ("national science theories 1:, physics")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"nato science series 1:, physics\") or (((\"nato science theories 1:, physics\") OR (\"national science theories 1:, physics\"))))".
• Removing quotes may allow a broader search: (( nato science series 1:, physics ) or ((( nato science theories 1:, physics ) OR ( national science theories 1:, physics )))).
• Adding a wildcard symbol may retrieve word variants: (("nato science series 1:, physics") or ((("nato science theories 1:, physics") OR ("national science theories 1:, physics"))))*.