My understanding is that if you are self-employed, a sole proprietor and eligible to file a schedule C, those deductions are still in place. The deductions that go away are those for un-reimbursed employee expenses who do not file a schedule C.
Say your employer requires you to have and maintain a professional membership, in my job that might be a SHRM or American Payroll Association membership, but doesn't reimburse you for it, if you itemized on your tax return, you could deduct those expense, but now, no more. Say your employer makes it mandatory for you to attend some conferences or training seminars. They pay for the conference but not for the travel expenses, not for your mileage or for the hotel or your meals while on travel, you can’t if you itemize take a deduction for any of those unreimbursed expenses now.
In my experience however, it would be very rare for an employer to not reimburse an employee for those type of professional or travel expenses.