There are different Business Directories :

Try all different Business Directories offered by
Every Engine has different results,
Most companies are listed in serveral directories
but the results are not the same ...

find products
and order them directly (example Sunglasses, Jeans, Scooters)

Products via Amazon
Business to Consumers - Companies froviding Products or Sevices for End Users
(example Restaurant)

Pagine Gialle Directory B2C
Yelp Directory B2C

Business to Business - Companies providing Products for Professionals
(example Manufacturer of Kitchens) Directory B2B

search through the Government
Italian Gov
Italy Gov Search
this search engine goes through
all the Italian ministeries,
maybe the person you are looking for
has been mentioned at some point.

search in another country

Phone Book of the
Phone Book of the
maybe the person you are looking for has moved
and can be cound through the directory of another country

good luck ...