This is Thrilling Wonder Stories for Fall 1944, cover by Rudolph Belarski. The ISFDB entry for this issue is here. I found this version of the cover at Pulp Covers. The quality of the Internet Archive scan is somewhat indifferent, which is a pity because some of the interior art is conceptually interesting. There is this uncredited piece illustrating Murray Leinster’s “The Eternal Now” and bearing the ominous caption “As they babbled desperate promises, Brett pressed the button.”

Or this (at least credited to Alex Schomburg) for Ray Cummings’s “The Gadget Girl.”

Or this uncredited illustration for John Russell Fearn’s story “The Ultimate Analysis,” which bears the caption “Suddenly the chorine was able to fathom all time, all space, and infinity.”

You can download and read the entire issue at The Internet Archive.