Perhaps you should try some spelling variations:
nonlinear particles » collinear particles, nonlinear vortices, nonlinear martingales
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 ( nonlinear particles theory ))) OR ( nonlinear material theory )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( nonlinear partial theory ) OR ( nonlinear particles theory ))) or ( nonlinear material theory ))".
• Adding a wildcard symbol may retrieve word variants: (((( nonlinear partial theory ) OR ( nonlinear particles theory ))) or ( nonlinear material theory ))*.