To execute a search in the site you can use the "SEARCH" button at the top of any page.
You can specify one or more words and press the button.
To search for a particular item for which you know the code enter the category code, followed by "." (point) then the identifier of the article (omitting the first letter if any).
For example, to search for article P.03.1118/19/PL, just enter the code "03.1118" in the search box and then click SEARCH (CERCA).
The search results can already be seen directly below the text box as you type code.