One of the things you can shop for in Amsterdam is antiques. Most well-known is the 'antique street', the Spiegelgracht and Nieuwe Spiegelstraat (which run from Herengracht to Rijksmuseum). Here you'll find a lot of antique stores.
On this page is a list of a selection of them.
Second hand bookstore Kok
Antique store in Spiegelstraat with paintings
Store in Spiegelstraat with Delft Blue
Store in Spiegelstraat with antique clocks