Plus you can identify medical education journals and look on their sites.

Dear Anique

For searching grey literature several free resources are available

1- opengrey database which is the database of European grey literature

http://www.opengrey.eu/

2- google scholar: however searching in google scholar can be a real challange as it is very inefficient

The most important subscription based grey literature database is

Dissertation abstract section of Proquest which is the American counterpart of opengrey.

In my experience for locating meeting abstracts ISI web of knowledge is one of the best databases as you can search the meeting abstracts published in important journals directly. However it is not free.

Ramin