There are three major housing corporations, De Key, DUWO and Ymere. These have one central information desk for student housing while the application process involves a waiting-list system.
DUWO also offers short stay accommodation via their website, where you can register and look for rooms online.
Another option is checking Woningnet, a housing corporation which offers apartments for rent in various regions. At their website you can choose to search for housing in the Amsterdam region.
Elynx is a site for expats living in The Netherlands. If you go to ‘Notices’ in their menu, then click on the ‘Offered: Shared Accommodation’ option, you will find various announcements.
Housing Anywhere is a housing platform on which students that go on exchange for a few months post their rooms available for renting. Incoming exchange students can respond to their announcements. This website operates on a student-to-student basis, without intermediaries.