title: Penetration of human spermatozoa into the human zona pellucida and the zona-free hamster egg: a study of fertile donors and infertile patients.
mesh_terms: D000818:Animals; D006224:Cricetinae; D005260:Female; D005298:Fertility; D005307:Fertilization in Vitro; D006801:Humans; D007248:Infertility, Male / Q000503:physiopathology*; D008297:Male; D009865:Oocytes / Q000502:physiology; D010063:Ovum / Q000502:physiology*; D013076:Sperm Count; D013081:Sperm Motility; D015044:Zona Pellucida / Q000502:physiology*