Results 11 to 20 of about 45,674 (256)
[Hypothesis of Genetic Diversity Selection in the Occurrence and Development of Lung Cancer: Molecular Evolution and Clinical Significance]. [PDF]
到目前为止,阐述肿瘤发生发展的单克隆假说不能自圆其说。遗传多样性选择假说将孟德尔遗传学与达尔文进化论联系起来,认为多克隆起源-单克隆选择-亚克隆扩张的肿瘤细胞群遗传多样性是选择压力的结果。正常细胞获得致癌驱动基因突变,相对于其他细胞具有选择优势,成为肿瘤启动细胞;在与肿瘤微环境(tumor microenvironment, TME)的互动中,绝大多数启动细胞会被人体自身免疫系统识别并杀灭,如果发生免疫逃逸,恶性肿瘤的发生率会极大增加,并发生亚克隆扩张、肿瘤内异质性等。本文提出遗传多样性选择假说 ...
Liu B.
europepmc +2 more sources
目的: 探究糖尿病合并冠心病患者临床护理中应用多样性护理的疗效。 方法: 将 2017 年 10 月 -2018 年 10 月,就诊我院符合糖尿病合并冠心病的诊断标准的患者 76 例,以随机数字表法分组为常规组(常规护理)、研究组(多样化护理干预),各纳入 38 例,对比血糖控制水平、生活质量、护理满意度。 结果: 干预后研究组血糖下降程度比常规组更显著 ...
晶 曲, 洪英 马, 璐璐 白
semanticscholar +1 more source
中外经济、文化日益频繁的交流,对国人所具备的外语水平提出了更加严格要求。从不同目的出发,如提高自身竞争力、兴趣爱好等,越来越多的学生开始选择除了英语之外的第二门外语,中学所开设第二外语课程逐步进入学生的生活中。根据2018年德意志学术交流中心(DAAD)提供的数据,目前中国已经有超过一万名中学生学习德语。德语学习者、爱好者数量快速增长,成为当前一个重要趋势。论文探讨了当前中学德语课程开设情况,探究更为有效的教学活动方式,希望为教学活动的顺利开展提供帮助。
雪岩 张
semanticscholar +1 more source
长江是我国第一大河流,全长达6300 km.长江是一条生命之河,它的活力来自于干流、支流、湖泊和湿地的血脉沟通形成的独特生命系统.长江流域是世界生物多样性的热点区域,分布有鱼类400余种,其中纯淡水鱼类350种左右,特有鱼类多达156种.长江中下游是东亚季风气候下形成的洪泛平原区域,湖泊星罗棋布,并与江河相连,生活有珍稀水生哺乳动物——白鱀豚和江豚.1980s初中下游湖泊面积约有23123 km2.19501970年间,沿江大建闸节制,除鄱阳湖(2933 km2)和洞庭湖(2625 km2)等外 ...
谢平, Xie Ping
semanticscholar +1 more source
Study on the Systematic Conservation Planning based conservation pattern of marine biodiversity in Xiamen [PDF]
随着经济发展、人口增加和城市化程度的加深,人类活动正在导致其赖以生存和发展的海洋生物多样性的减少甚至丧失。建立海洋保护区是目前保护海洋生物多样性的重要途径。然而传统海洋保护区规划往往仅考虑保护少数物种,而缺乏对海洋生物多样性所依托的海岸生境的保护的考虑;很多保护区范围是人为划定而缺少对保护成本的考虑,导致付出很高的成本却没有达到生物多样性保护的目标,有些地方甚至由于成本过高导致保护区形同虚设。研究平衡生物多样性保护和社会经济发展 ...
陈璟明
core
First confirmed breeding of the Brown Hornbill in China, documented through cooperative feeding in Shangyong Protected Area. ABSTRACT The Brown Hornbill (Anorrhinus austeni), a Near Threatened frugivore, reaches the northern edge of its distribution in southern Yunnan, China, yet breeding had not been previously documented with site‐attributed nests in
Junsong Li +8 more
wiley +1 more source
This research reveals the functional stability of mixed species foraging flocks (MSF) and their foraging height change with different taxonomic differences along the elevational gradient at Knuckles Montane Reserve, Sri Lanka. This offers new insights into how MSFs sustain with the elevational gradients supporting the altitudinal shifting species ...
Vimukthi. R. Gunasekeara +3 more
wiley +1 more source
Evolutionary algorithms in dynamic environments [PDF]
The file attached to this record is the author's final peer reviewed version.Evolutionary algorithms (EAs) are widely and often used for solving stationary optimization problems where the fitness landscape or objective function does not change during the
Wang, Dingwei +2 more
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Abstract Currently, scholarship on education to foster connectedness with nature primarily focuses on children. As adults likewise face the disconnection from nature and play a key role in influencing children, it is important to understand how they perceive, engage in, and benefit from relevant programmes.
Xiaoxue Chen, Zuyi Lyu, Junxi Qian
wiley +1 more source
Study on latitudinal gradient of species diversity in forest communities [PDF]
森林群落结构和物种多样性的空间分异规律一直是生态学研究的热点问题。近年来,关于森林群落结构的描述与物种多样性的测定方法等研究也都有所发展,但这些研究大多是对森林生态系统的定性描述,而且方法不一,数据之间也缺乏可比性。 群落的组成结构是群落的重要标志,研究群落结构是研究群落物种多样性意义的理论基础,所以从群落组成结构的角度来探讨生物群落的物种多样性具有重要的意义,为进一步深入研究生物多样性功能及确定功能群提供理论基础 ...
孙影
core

