Perhaps you should try some spelling variations:
nonlinear material » nonlinear materials, nonlinear matrix, nonlinear media
nonlinear particle » collinear particles, linear particle, nonlinear price
material theory » materials theory
partial theory » spatial theory, particles theory, partial tears

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: (((( nonlinear partial theory ) OR ( nonlinear particle theory ))) OR ( nonlinear material theory )).
• Adding a wildcard symbol may retrieve word variants: (((( nonlinear partial theory ) or ( nonlinear particle theory ))) or ( nonlinear material theory ))*.