SHELDON: Go ahead.
That's the only DOCTORATE you'll ever get.
The Big Bang Theory Season 6, Episode 9
I've been thinking about getting my DOCTORATE,
and he wants to teach. Why not?
The Big Bang Theory Season 8, Episode 2
Is it any wonder
he doesn't have a DOCTORATE?
The Big Bang Theory Season 4, Episode 18
What's a world-renowned entomologist
with a DOCTORATE...
The Big Bang Theory Season 3, Episode 2
I have a DOCTORATE in astrophysics
and I'm every bit as awesome
The Big Bang Theory Season 10, Episode 11