Embryo nearly matured, arrow showing embryonic bud; 13.

接近成熟的胚，箭头所指为胚芽处；

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Results The detection rate of mass, yolk sac, embryonic bud, embryonic heartbeat and ovary was higher in the TVS or TAS TVS test than those in the TAS test (P<0.01).

结果TVS及TAS TVS对附件区包块、卵黄囊、胎芽、胎心搏动、宫内假孕囊、卵巢的检出率远较TAS高，差异均有统计学意义（P<0.01）。

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Tooth enamel begins to form in the human embryo when a specialised layer of cells, called ameloblasts, in the embryonic tooth bud secretes amelogenin proteins.

BBC: By BBC News Online Science Editor Dr David Whitehouse