If you could run out and get a PhD,
that might make her like you.
The Big Bang Theory Season 8, Episode 23
I have a PhD in astrophysics.
The Big Bang Theory Season 10, Episode 18
A PowerPoint presentation
by Sheldon Cooper, PhD."
The Big Bang Theory Season 3, Episode 15
I must say, Amy, I was very impressed
to see that Bernadette got her PhD.
The Big Bang Theory Season 4, Episode 24
and where Leonard got his PhD,
so it may have gone downhill.
The Big Bang Theory Season 10, Episode 23