Perhaps you should try some spelling variations:
"mathematics optimization" » "mathematical optimization"
"materials optimization" » "material optimization", "criteria optimization", "models optimization"
"automatic estimation" » "automatic optimization", "automatic extraction", "automatic evaluation"

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: (((("mathematics optimization") OR ("materials optimization"))) OR ("automatic estimation")).
• Removing quotes may allow a broader search: (((( mathematics optimization ) or ( materials optimization ))) or ( automatic estimation )).
• Adding a wildcard symbol may retrieve word variants: (((("mathematics optimization") or ("materials optimization"))) or ("automatic estimation"))*.