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

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 ((("automatic optimization") OR ("automatic estimation"))))) OR ("materials optimization")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"mathematics optimization\") or (((\"automatic optimization\") OR (\"automatic estimation\"))))) or (\"materials optimization\"))".
• Removing quotes may allow a broader search: (((( mathematics optimization ) or ((( automatic optimization ) OR ( automatic estimation ))))) or ( materials optimization )).
• Adding a wildcard symbol may retrieve word variants: (((("mathematics optimization") or ((("automatic optimization") OR ("automatic estimation"))))) or ("materials optimization"))*.