Mongolia;
Saikexing;
Reproductive;
Biotechnology;
Co.;
Ltd.;
Helingeer;
011517;
P.R.China;
Center;
for;
Animal;
Genetic;
Resources;
of;
Mongolia;
Plateau;
Inner;
Mongolia;
University;
Hohhot;
010021;
P.R.China;
PMSG; 小鼠品系; 胚胎发育; 超数排卵; HCG; 外源性促性腺激素; 滋养层细胞; 囊胚发育率;