I am looking for a single word for describing dolls that looks like real human beings.
Lifelike would seem to be the obvious choice.
Verisimilitude captures for 'close to real'.
If you are looking for an adjective which means apparently (but not actually) real, try virtual. Using the adjective form, you could say the dolls are virtually human.¹
Verisimilitude is a noun. Verisimilar is appropriate but sounds like two words.
Would realistic fit the bill?
Other alternatives are naturalistic, graphic, vivid, convincing, compelling
The last word is my preferred option
If you want to say that they look like humans, try humanoid.
Dolls of human size which are used for showing clothes in shop windows are called mannequins.
It may be obvious, it may be literal and it may be hyphenated but how about:
The dolls were so human-like