Perhaps you should try some spelling variations:
"opera philosophia mechanica" » "opera philosophical mechanical", "opera philosophical mechanics", "opera philosophie mechanique", "opera philosophy mechanica", "pia philosophia mechanica", "verae philosophiae mechanica"
"opera philosophica fennica" » "opera philosophical feminism", "opera philosophical ethical", "opera philosophical medical", "general philosophical fennica", "several philosophical fennica"

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"opera philosophica fennica\") OR (\"opera philosophia mechanica\"))".
• Removing quotes may allow a broader search: (( opera philosophica fennica ) OR ( opera philosophia mechanica )).
• Adding a wildcard symbol may retrieve word variants: (("opera philosophica fennica") OR ("opera philosophia mechanica"))*.