Perhaps you should try some spelling variations:
"olefins metathesis" » "opening metathesis", "olefin metathese", "olefins synthesis"
"alumina metathesis" » "alkene metathesis", "alkyne metathesis", "alumina synthesis"
"closing metathesis" » "opening metathesis"

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: (("olefin metathesis") OR ((((("olefins metathesis") OR ("alumina metathesis"))) OR ("closing metathesis")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"olefin metathesis\") or (((((\"olefins metathesis\") OR (\"alumina metathesis\"))) or (\"closing metathesis\"))))".
• Removing quotes may allow a broader search: (( olefin metathesis ) or ((((( olefins metathesis ) OR ( alumina metathesis ))) or ( closing metathesis )))).
• Adding a wildcard symbol may retrieve word variants: (("olefin metathesis") or ((((("olefins metathesis") OR ("alumina metathesis"))) or ("closing metathesis"))))*.