doktorka

1. doctor; physician
   Doktorka mi je prepisala antibiotik. — The doctor prescribed me an antibiotic.
   Dobar dan, doktorka, boli me grlo. — Good afternoon, doctor, my throat hurts.
2. (of an academic degree) woman holding a doctorate
   Ona je doktorka hemije i radi na fakultetu. — She has a doctorate in chemistry and works at the university.

In Serbia a female doctor is usually addressed as "doktorka" (vocative doktorka or doktorko). The Serbian degree doktor nauka is a PhD; it usually corresponds to the Russian kandidat nauk, not to the Russian doktor nauk.