A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Ph.D
[Ph.D 词源字典]
attested from 1869; abbreviation of Latin
Philosophiae Doctor
"Doctor of Philosophy."
[Ph.D etymology, Ph.D origin, 英语词源]