Search for "subject:(Kovalevskai︠a︡, S. V. (Sofʹi︠a︡ Vasilʹevna), 1850-1891)" found nothing
Try limiting your search to just one of these... subject:(Kovalevskai︠a︡, or S. or V. or (Sofʹi︠a︡ or Vasilʹevna), or 1850-1891)
Try the "More search options" page.