To switch off the Add to Campaign, Export to Excel and Send Email buttons add these Settings with a value of false (shown below). This permission feature was provided in October 2015.
Setting Name: AdvancedSearchSendToCampaign
Setting Value: True/False
Setting Name: AdvancedSearchExportToExcel
Setting Value: True/False
Setting Name: AdvancedSearchSendToEmail
Setting Value: True/False
Note: To enable the buttons no setting is required. If the Settings have been added to your site and you wish to enable the buttons, set the value to True or remove the Settings.