Perhaps you should try some spelling variations:
22optical materials » optical materials, acoustical materials, optics materials
optical material » optical materials, optimal maternal, optics materials
optic materials » optical materials, basic materials, ionic materials

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• If you are trying to use Boolean operators, they must be ALL CAPS: %((((22optical materials) OR (optic materials))) OR (optical material))%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%((((22optical materials) OR (optic materials))) or (optical material))%22".
• Adding a wildcard symbol may retrieve word variants: %((((22optical materials) OR (optic materials))) or (optical material))%22*.