正常情况下黑色素细胞存在于() ["真皮","基底细胞层","血管周围","颗粒层"]
下列哪项措施对股骨颈骨折后股骨头缺血坏死的治疗不利() ["让患者扶双拐,长期不负重","手术加压固定","早期离床活动,促进局部血运","股骨头钻孔,促进血管长入","采用股骨头内血管植入"]
下列不是急性咽炎的症状的是() ["咽部干燥","咽痛","耳痛","四肢酸痛","张口困难"]
胎儿发育过程恰当的是() ["妊娠8周末,从外观可分辨男女","妊娠20周末,胎儿体重约为500g","妊娠24周末,胎儿体重约为1000g","妊娠32周末,胎儿体重约为2000g","妊娠36周末.胎儿体重约为2500g"]
黑素细胞起源于() ["中胚层的神经嵴","中胚层的神经管","外胚层的神经嵴","外胚层的神经管"]
影响癫痫发作有哪些因素?