全文获取类型
收费全文 | 4088篇 |
免费 | 343篇 |
国内免费 | 1篇 |
专业分类
4432篇 |
出版年
2023年 | 40篇 |
2022年 | 81篇 |
2021年 | 139篇 |
2020年 | 106篇 |
2019年 | 111篇 |
2018年 | 115篇 |
2017年 | 111篇 |
2016年 | 132篇 |
2015年 | 218篇 |
2014年 | 210篇 |
2013年 | 284篇 |
2012年 | 301篇 |
2011年 | 292篇 |
2010年 | 232篇 |
2009年 | 181篇 |
2008年 | 170篇 |
2007年 | 158篇 |
2006年 | 138篇 |
2005年 | 124篇 |
2004年 | 111篇 |
2003年 | 103篇 |
2002年 | 82篇 |
2001年 | 58篇 |
2000年 | 75篇 |
1999年 | 38篇 |
1998年 | 23篇 |
1997年 | 34篇 |
1996年 | 33篇 |
1995年 | 24篇 |
1994年 | 30篇 |
1993年 | 25篇 |
1992年 | 43篇 |
1991年 | 26篇 |
1990年 | 36篇 |
1989年 | 25篇 |
1988年 | 21篇 |
1987年 | 32篇 |
1986年 | 29篇 |
1985年 | 28篇 |
1984年 | 19篇 |
1983年 | 19篇 |
1982年 | 22篇 |
1981年 | 23篇 |
1980年 | 16篇 |
1979年 | 23篇 |
1978年 | 17篇 |
1977年 | 25篇 |
1975年 | 17篇 |
1972年 | 16篇 |
1970年 | 15篇 |
排序方式: 共有4432条查询结果,搜索用时 0 毫秒
1.
Lucas Henriques Viscardi Danilo Oliveira Imparato Maria Ctira Bortolini Rodrigo Juliani Siqueira Dalmolin 《Molecular biology and evolution》2021,38(3):735
The origin of nervous systems is a main theme in biology and its mechanisms are largely underlied by synaptic neurotransmission. One problem to explain synapse establishment is that synaptic orthologs are present in multiple aneural organisms. We questioned how the interactions among these elements evolved and to what extent it relates to our understanding of the nervous systems complexity. We identified the human neurotransmission gene network based on genes present in GABAergic, glutamatergic, serotonergic, dopaminergic, and cholinergic systems. The network comprises 321 human genes, 83 of which act exclusively in the nervous system. We reconstructed the evolutionary scenario of synapse emergence by looking for synaptic orthologs in 476 eukaryotes. The Human–Cnidaria common ancestor displayed a massive emergence of neuroexclusive genes, mainly ionotropic receptors, which might have been crucial to the evolution of synapses. Very few synaptic genes had their origin after the Human–Cnidaria common ancestor. We also identified a higher abundance of synaptic proteins in vertebrates, which suggests an increase in the synaptic network complexity of those organisms. 相似文献
2.
3.
Spencer G. Lucas Bolat U. Bayshashov Lyubov A. Tyutkova Ayzhan K. Zhamangara Bolat Z. Aubekerov 《Pal?ontologische Zeitschrift》1997,71(3-4):305-314
At Aktau Mountain in the Ili depression of eastern Kazakstan, fossil mammals that encompass the Paleogene-Neogene boundary occur at three stratigraphic levels. The lowest level is in the lower Kyzylbulak Formation and produces Brontotheriidae and the hyracodontidArdynia and is tentatively assigned a late Eocene (Ergilian) age. The lower part of the overlying Aktau Formation produces fossils of the giant rhinocerosParaceratherium and is tentatively assigned a late Oligocene (Tabenbulukian) age. The upper part of the Aktau Formation yields a fossil mammal assemblage that includesGomphotherium,Stephanocemas, Brachypotherium andLagomeryx. It is clearly of Miocene age, probably late early Miocene (late Burdigalian), a correlative of European Reference Level MN 5 and the late Shanwangian of China. The Paleogene-Neogene boundary at Aktau Mountain thus is in the Aktau Formation. 相似文献
4.
Alba Luengo Zhaoqi Li Dan Y. Gui Lucas B. Sullivan Maria Zagorulya Brian T. Do Raphael Ferreira Adi Naamati Ahmed Ali Caroline A. Lewis Craig J. Thomas Stefani Spranger Nicholas J. Matheson Matthew G. Vander Heiden 《Molecular cell》2021,81(4):691-707.e6
- Download : Download high-res image (172KB)
- Download : Download full-size image
5.
G L Lucas 《Plastic and reconstructive surgery》1987,80(1):92-94
Fowler's central slip tenotomy for old mallet deformity is a well-known, but apparently seldom used procedure. Although the vast majority of patients with mallet finger can be successfully treated by well-known conservative techniques, occasional patients, such as the 11 reported here, will have enough difficulty with a chronic mallet finger to warrant rebalancing of the extensor apparatus by means of central slip tenotomy. 相似文献
6.
Blanco Pablo J. Müller Lucas O. Watanabe Sansuke M. Feijóo Raúl A. 《Biomechanics and modeling in mechanobiology》2020,19(5):1663-1678
Biomechanics and Modeling in Mechanobiology - The goal of this work is to assess the impact of vascular anatomy definition degree in the predictions of blood flow models of the arterial network. To... 相似文献
7.
8.
Dominique Martinez Antoine Chaffiol Nicole Voges Yuqiao Gu Sylvia Anton Jean-Pierre Rospars Philippe Lucas 《PloS one》2013,8(4)
Insects and robots searching for odour sources in turbulent plumes face the same problem: the random nature of mixing causes fluctuations and intermittency in perception. Pheromone-tracking male moths appear to deal with discontinuous flows of information by surging upwind, upon sensing a pheromone patch, and casting crosswind, upon losing the plume. Using a combination of neurophysiological recordings, computational modelling and experiments with a cyborg, we propose a neuronal mechanism that promotes a behavioural switch between surge and casting. We show how multiphasic On/Off pheromone-sensitive neurons may guide action selection based on signalling presence or loss of the pheromone. A Hodgkin-Huxley-type neuron model with a small-conductance calcium-activated potassium (SK) channel reproduces physiological On/Off responses. Using this model as a command neuron and the antennae of tethered moths as pheromone sensors, we demonstrate the efficiency of multiphasic patterning in driving a robotic searcher toward the source. Taken together, our results suggest that multiphasic On/Off responses may mediate olfactory navigation and that SK channels may account for these responses. 相似文献
9.