ступенями
• Some tumours may progress in a stepwise fashion.
• The stored energy is released in a stepwise manner (or step by step).
• The concrete lining was poured in lifts of 5 ft.
• The process is carried out in stages (or in steps, or stepwise).
• Narrow down the proportional band in small steps.
Источник:
Русско-английский научно-технический словарь
на Gufo.me