xanthine dehydrogenase黄嘌呤脱氢酶 xanthoma disseminatum(拉)播散性黄瘤 xenodiagnosis异体接种诊断法,宿主诊断法 xerodermia干皮病,皮肤干燥病 x-linked dominant inheritancex连锁显性遗传 x-linked dominantx伴性显性遗传