Can I disable Global Search for specific roles, such as partner roles?

Search results depend on the data access granted to each user by their role and other factors, so partner roles don't see any results they aren't permitted to see. If you want to remove the Global Search box at the top of the page altogether, however, you can't remove it by role. You can either remove Global Search for everyone, or for specific users. To remove the Global Search box for specific users or for everyone, set the profile option Global Search Enabled (FUSION_APPS_SEARCH_ENABLED) using the Manage Administrator Profile Values task in Setup and Maintenance.