Perhaps you should try some spelling variations:
"scientific optical" » "scientific practical", "scientific clinical", "scientific article"
"scientific medical" » "scientific medicine", "scientific technical", "scientific clinical"
"scientific ethical" » "scientific technical", "scientific practical"

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: (((("scientific optical") OR ("scientific medical"))) OR ("scientific ethical")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"scientific optical\") OR (\"scientific medical\"))) or (\"scientific ethical\"))".
• Removing quotes may allow a broader search: (((( scientific optical ) OR ( scientific medical ))) or ( scientific ethical )).
• Adding a wildcard symbol may retrieve word variants: (((("scientific optical") OR ("scientific medical"))) or ("scientific ethical"))*.