全文获取类型
收费全文 | 2886篇 |
免费 | 212篇 |
国内免费 | 223篇 |
出版年
2024年 | 5篇 |
2023年 | 44篇 |
2022年 | 119篇 |
2021年 | 193篇 |
2020年 | 111篇 |
2019年 | 131篇 |
2018年 | 120篇 |
2017年 | 117篇 |
2016年 | 156篇 |
2015年 | 200篇 |
2014年 | 215篇 |
2013年 | 247篇 |
2012年 | 273篇 |
2011年 | 249篇 |
2010年 | 153篇 |
2009年 | 123篇 |
2008年 | 149篇 |
2007年 | 114篇 |
2006年 | 94篇 |
2005年 | 72篇 |
2004年 | 69篇 |
2003年 | 49篇 |
2002年 | 43篇 |
2001年 | 32篇 |
2000年 | 24篇 |
1999年 | 30篇 |
1998年 | 17篇 |
1997年 | 21篇 |
1996年 | 25篇 |
1995年 | 13篇 |
1994年 | 20篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1968年 | 3篇 |
排序方式: 共有3321条查询结果,搜索用时 46 毫秒
41.
42.
Yang Jing Xun HongWei Niu Lu He Hongli Cheng Yunqing Zhong Xiaofang Zhao Qianqian Xing Guojie Liu Jianfeng Yang Xiangdong 《Transgenic research》2021,30(5):675-686
Transgenic Research - Soybean seeds are an ideal host for the production of recombinant proteins because of their high content of proteins, long-term stability of seed proteins under ambient... 相似文献
43.
44.
Zhijie Ren Fenglin Bai Jingwen Xu Li Wang Xiaohan Wang Qian Zhang Changxin Feng Qi Niu Liying Zhang Jiali Song Fang Bao Liangyu Liu Yikun He Ligeng Ma Wang Tian Congcong Hou Legong Li 《植物学报(英文版)》2021,63(12):2150-2150
Grain size is determined by the size and number of cells in the grain. The regulation of grain size is crucial for improving crop yield; however, the genes and molecular mechanisms that control grain size remain elusive. Here, we report that a member of the detoxification efflux carrier /Multidrug and Toxic Compound Extrusion (DTX/MATE) family transporters, BIG RICE GRAIN 1 (BIRG1), negatively influences grain size in rice (Oryza sativa L.). BIRG1 is highly expressed in reproductive organs and roots. In birg1 grain, the outer parenchyma layer cells of spikelet hulls are larger than in wild-type (WT) grains, but the cell number is unaltered. When expressed in Xenopus laevis oocytes, BIRG1 exhibits chloride efflux activity. Consistent with this role of BIRG1, the birg1 mutant shows reduced tolerance to salt stress at a toxic chloride level. Moreover, grains from birg1 plants contain a higher level of chloride than those of WT plants when grown under normal paddy field conditions, and the roots of birg1 accumulate more chloride than those of WT under saline conditions. Collectively, the data suggest that BIRG1 in rice functions as a chloride efflux transporter that is involved in mediating grain size and salt tolerance by controlling chloride homeostasis. 相似文献
45.
46.
Jinhua Xiao Xianqin Wei Yi Zhou Zhaozhe Xin Yunheng Miao Hongxia Hou Jiaxing Li Dan Zhao Jing Liu Rui Chen Liming Niu Guangchang Ma Wenquan Zhen Shunmin He Jianxia Wang Xunfan Wei Weihao Dou Zhuoxiao Sui Dawei Huang 《遗传学报》2021,48(3):225-236
Figs and fig pollinators are one of the few classic textbook examples of obligate pollination mutualism. The specific dependence of fig pollinators on the relatively safe living environment with sufficient food sources in the enclosed fig syconia implies that they are vulnerable to habitat changes. However, there is still no extensive genomic evidence to reveal the evolutionary footprint of this long-term mutually beneficial symbiosis in fig pollinators. In fig syconia, there are also non-pollinator species. The non-pollinator species differ in their evolutionary and life histories from pollinators. We conducted comparative analyses on 11 newly sequenced fig wasp genomes and one previously published genome. The pollinators colonized the figs approximately 66.9 million years ago, consistent with the origin of host figs. Compared with nonpollinators, many more genes in pollinators were subject to relaxed selection. Seven genes were absent in pollinators in response to environmental stress and immune activation. Pollinators had more streamlined gene repertoires in the innate immune system, chemosensory toolbox, and detoxification system. Our results provide genomic evidence for the differentiation between pollinators and nonpollinators. The data suggest that owing to the long-term adaptation to the fig, some genes related to functions no longer required are absent in pollinators. 相似文献
47.
48.
Song Wang Quan Quan Cheng Meng Weinan Chen Yiqi Luo Shuli Niu 《Journal of Plant Ecology》2021,14(3):541
增温对高寒草甸生态系统碳氮循环耦合关系的影响
陆地生态系统碳吸收受土壤氮素可用性的调节。然而,全球变化背景下的不同生态系统组分的碳氮比及其所反映的碳氮循环耦合关系尚不十分清楚。本文运用数据同化的方法,将一个高寒草甸增温试验的14组数据同化到草地生态系统模型中,从而评估了增温如何影响陆地生态系统的碳氮循环耦合关系。研究结果表明,增温提高了土壤氮素的有效性,降低了土壤活性碳库的碳氮比,导致植物对土壤氮的吸收增加。但是由于植物叶片吸收的碳比吸收的氮增加更多,使得叶片中碳氮比增加,而根部的碳输入增加则低于氮的增加,导致根部的碳氮比减少。同时,增温降低了凋落物碳氮比,可能是在土壤高氮有效性的条件下,凋落物氮的固定得到增强;而且增温加速了凋落物的分解。同时增温还增加了慢速土壤有机质的碳氮比,使得该土壤碳库的碳固存潜力增大。由于大多数模型在不同的环境中通常使用相对固定的碳氮比,本研究所发现的气候变暖条件下碳氮比的差异变化可为模型参数化提供一个有效的参考,有利于模型对未来气候变化背景下生态系统碳氮耦合关系响应的预测。 相似文献
49.
50.