Yes you can. You just have to pay for the second one. Steemit Inc will provide you with your first account free of charge in exchange for some private information about you. But you can buy more accounts.
Blocktrades has a great tool to let you create accounts : https://blocktrades.us/create-steem-account. Their current minimum send is about 4.1 STEEM to get an account. You'll get an account with 3 STEEM powered up.
You can also use steemconnect's tool to create a second account: https://v2.steemconnect.com/accounts/create. It will cost either 3 STEEM or 0.1 STEEM and a 15 SP delegation to the new account.