WorldCat (the world catalogue) includes records for over 8 million theses from many countries, in many languages and links to those available in full text. WorldCat also includes all theses held by Australian universities.
In Basic search type in title, author and/or subject keywords (then click search). On the left of the Results page, under Format, select Thesis / dissertation, Year and / or Language. For theses available in full text, simply select Computer file under Format.
Italian theses
You can search the catalogues of international university libraries through LibWeb, or alternatively, a list of Italian libraries can be found here.
For more information, check out the Thesis Library Guide.