פירוש על קידושין 67:6

To find out why women are exempt from time-bound commandments, the Talmud seeks a paradigm and finds it in tefillin. Women are exempt from tefillin, because tefillin is compared to the study of Torah in Deuteronomy 6:7-8 (the first paragraph of Shema). And from Deuteronomy 11:19 we derive that women are exempt from Talmud Torah.