Can have two iCloud different account in the same device?

The account signed into in System Preferences (or Settings)>iCloud is known as the 'primary account'. You can ad one or more 'Secondary accounts' in System preferences>Mail, Contacts and Calendars.

Those data will appear alongside the Primary Account's data, though you don't get 'push' email - the mail is checked at intervals. The Secondary account(s) cannot access Photo Stream or Find My Mac.

Sorry, not Documents. I quote:

'iCloud Bookmarks, Photo Stream, Documents in the Cloud, Backup (iOS), Back to My Mac (OS X), and Find My iPhone, iPad, iPod touch, or Mac can only be used with one iCloud account at a time (the "primary" account).'

The only thing you can do would be to create a second user account on your Mac and create a new iCloud primary account on that. Fast user switching would allow you to have both user accounts running at the same time and switch between them very quickly, but uploading documents created in one account into the other is more complicated - you would have to save a copy into the Shared folder in Users so that it was accessble by the other account.