Contratacion 5580

I am reading Lope Ruiz de Esparza's entry on Catalogo de Pasajeros a Indias Volumen VII, and comparing it with the original document posted here on nuestros ranchos, thanks to Arturo Ramos. I'm just curious, where on the internet can you browse through these books of "Contratacion"? I am not that familiar with the PARES website, so I'm not really sure how to look for these documents if they are available at all online.

Steve in NC