Perhaps you should try some spelling variations:
collinear particles » collider particle, colloidal particles, colliding particles
nonlinear material » nonlinear materials, nonlinear matrix, nonlinear media
particles theory » particle theory, particles through
material theory » materials theory
partial theory » particle theory, spatial 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 ( collinear particles theory ))) OR ( nonlinear material theory )).
• Adding a wildcard symbol may retrieve word variants: (((( nonlinear partial theory ) or ( collinear particles theory ))) or ( nonlinear material theory ))*.