Please indicate the closing hours and business days of the businesses with the category named Doctors.
closing hours refer to closing_time; business days refer to day_id from Business_Hours;
SELECT DISTINCT T3.opening_time, T3.day_id FROM Business_Categories AS T1 INNER JOIN Categories AS T2 ON T1.category_id = T2.category_id INNER JOIN Business_Hours AS T3 ON T1.business_id = T3.business_id INNER JOIN Days AS T4 ON T3.day_id = T4.day_id WHERE T2.category_name = 'Doctors'