
I'm getting my PhD.
The Big Bang Theory Season 4, Episode 24

I have a PhD in astrophysics.
The Big Bang Theory Season 10, Episode 18

If you could run out and get a PhD,
that might make her like you.
The Big Bang Theory Season 8, Episode 23

"Why Sheldon Cooper, PhD...
The Big Bang Theory Season 3, Episode 15

A PowerPoint presentation
by Sheldon Cooper, PhD."
The Big Bang Theory Season 3, Episode 15