This is the 18353rd most frequent Russian word.
экземплярах
"Copies" or "specimens" in the context of quantity.
The word "экземплярах" here refers to copies or individual prints of books.
Эти книги были напечатаны в ограниченных экземплярах.
These books were printed in limited copies.
In this sentence, "экземпляров" refers to physical units of the magazine.
Мы получили несколько экземпляров нового журнала.
We received several copies of the new magazine.
Here, "экземплярах" means individual instances or sets of the signed document.