33
/ru/
AIzaSyAYiBZKx7MnpbEhh9jyipgxe19OcubqV5w
October 1, 2025
Create a timeline
Public Timelines
For education
For educational institutions
For teachers
For students
Cabinet
For educational institutions
For teachers
For students
Open cabinet
FAQ
Получить премиум
Close
Create a timeline
Public timelines
Library
FAQ
About & Feedback
Соглашение
Приватность
Библиотека
FAQ
Support 24/7
Cabinet
Get premium
Donate
The service accepts bank transfer (ACH, Wire) or cards (Visa, MasterCard, etc). Processed by Stripe.
Secured with SSL
Редактировать
Скачать
Export
Создать копию
Premium
Встроить в сайт
Share
polio
Category:
Иное
Обновлено:
26 ноя 2017
1
0
457
Авторы
Created by
Sophie
Attachments
Comments
eee
By
Sophie
26 ноя 2017
0
0
488
События
Polio was the most feared disease of this time.
Jonas Salk announced that he was developing a trial vaccine for polio.
The Salk vaccine was tested on 1.8 million schoolchildren.
About & Feedback
Соглашение
Приватность
Библиотека
FAQ
Support 24/7
Cabinet
Get premium
Donate
The service accepts bank transfer (ACH, Wire) or cards (Visa, MasterCard, etc). Processed by Stripe.
Secured with SSL
Comments