创新需要提出问题，问题产生于（）。 ["好奇","质疑","想象","继承"]
以下哪些选项可能是科研选题的来源的是（） [" 从护理新领域中选题"," 从文献中获取选题的灵感"," 结合理论进行选题"," 选择与已有研究类似的题目"," 从实践中发现研究问题"]
叶序类型
人体维生素D主要来源于（）。 ["皮肤合成的内源性维生素D","蛋黄中的维生素D","猪肝中的维生素D","鱼类提供维生素D","谷物中的维生素D"]
Which of these terms refers to call issues that cause variations in timing or time of arrival？（） ["queuing","jitter","packet loss","digitized sampling","signal-to-noise ratio ratio"]
中缝大核
