两个英语短语的辨析at present与at the present time有嘛区别,我查了三本词典,词义都那么模糊,

at present adv.现在,目前
I have no enough material in hand at present.
目前我手头没有足够的资料.
At present,I don't want to get married.
目前,我还不想结婚.
at the present time 现在
At the present time,NMR equipment is very expensive.
目前,核磁共振仪还是很昂贵的.
就意思来说,2者完全一样,只是at present更多是被当副词来修饰动词.at the present time拿来当状语的时候更多.
另外就是后者没前者常用.