Yes, with proper notice to the tenant. Tenants have a right to privacy. Unannounced entry and inspection of the property infringes on that right to privacy. The best practice is to include in the lease the conditions under which the landlord may visit, enter, and inspect the property and the amount of notice required.
There may be limited exceptions to the notice requirement, such as during an emergency situation that threatens the life or health of the tenant or others.