How to implement a 301 redirect for all posts in a wordpress blog?

Question

Blogs

Guys, hello! I transfer the blog to another domain, glue the domains together.
Created the following .htaccess:
RewriteCond %{HTTP_HOST} ^www.oldsite\.ru$ [NC]
RewriteRule ^(.*)$ newsite.ru/$1 [R=301,L]
RewriteCond %{HTTP_HOST} ^oldsite\.ru $ [NC]
RewriteRule ^(.*)$ newsite.ru/$1 [R=301,L]
Everything is great, I started to redirect.... But only from the main one, if you go to oldsite.ru/statya it remains on the same domain , does not redirect... Why and how to deal with it? How to set up a redirect from all posts? Why doesn't .htaccess work on all pages?
System: Wordpress