Delete Permission at opportunity line

Hi,

I have a restriction in our CRM that any sales person can't delete anything. They can create, edit, change accounts, contacts, opportunities, quotes, orders... but no delete, but I have a problem with detail of this entities because I want they can add/change/delete (quote line, opportunities line, sales line...).

For example, I quit delete permission at opportunities entity, so they can't delete opportunity details (line of opportunity). There is any other permission only on details of entities?

Thanks