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

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"nonlinear partial theory\") OR (\"nonlinear particle theory\"))) OR (\"nonlinear material theory\"))*".
• Removing quotes may allow a broader search: (((( nonlinear partial theory ) OR ( nonlinear particle theory ))) OR ( nonlinear material theory ))*.