Microscopy image of a PGA at day 8 showing the early tissues supporting the embryo, including the amniotic sac and the yolk sac-like structures, surrounded by (extra-embryonic) mesoderm tissue.

The Nature Index 2025 Research Leaders — previously known as Annual Tables — reveal the leading institutions and countries/territories in the natural and health sciences, according to their output in ...

"The present publication is the fourth of a series of five researches concerning the histology and physiology of the early ovum; 2 to 7-8th week."--p. [2] siris_sil_243108 ...