The ability to search via Transaction history (if that's what you meant) basically depends on one exchanger to another. Some will offer a more comprehensive sorting functions while other don't even let you browse more than an hour of transaction history. So far I've never seen one offering such detailed service but maybe what you can do to overcome that is by looking at the volume of trade occurring at a specific hour.
Wait, so you wanna know the NUMBER of transactions of an exchange, i guess in a specific amount of time, right? You can definitely see the volume of all transactions each hour on pretty much all exchanges but im not sure about the number of transactions, why would you need such thing anyway?