Perhaps you should try some spelling variations:
materials optimization » material optimization, criteria optimization
models optimization » modeling optimization
model optimization » modeling optimization, level optimization, global optimization

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: ((((materials optimization) OR (mathematical optimization))) OR (((models optimization) OR (model optimization)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((materials optimization) or (mathematical optimization))) or (((models optimization) OR (model optimization))))".
• Adding a wildcard symbol may retrieve word variants: ((((materials optimization) or (mathematical optimization))) or (((models optimization) OR (model optimization))))*.