全文获取类型
收费全文 | 3280篇 |
免费 | 266篇 |
国内免费 | 2篇 |
专业分类
3548篇 |
出版年
2023年 | 8篇 |
2022年 | 44篇 |
2021年 | 56篇 |
2020年 | 45篇 |
2019年 | 55篇 |
2018年 | 75篇 |
2017年 | 64篇 |
2016年 | 96篇 |
2015年 | 158篇 |
2014年 | 177篇 |
2013年 | 197篇 |
2012年 | 276篇 |
2011年 | 241篇 |
2010年 | 177篇 |
2009年 | 147篇 |
2008年 | 205篇 |
2007年 | 237篇 |
2006年 | 201篇 |
2005年 | 181篇 |
2004年 | 206篇 |
2003年 | 150篇 |
2002年 | 137篇 |
2001年 | 29篇 |
2000年 | 22篇 |
1999年 | 18篇 |
1998年 | 34篇 |
1997年 | 20篇 |
1996年 | 22篇 |
1995年 | 20篇 |
1994年 | 20篇 |
1993年 | 14篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 15篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 7篇 |
1974年 | 6篇 |
1966年 | 5篇 |
1931年 | 6篇 |
排序方式: 共有3548条查询结果,搜索用时 15 毫秒
81.
82.
83.
Boris R. Krasnov Georgy S. Shenbrot Luther van der Mescht Elizabeth M. Warburton Irina S. Khokhlova 《Ecography》2019,42(5):1000-1011
We studied patterns of phylogenetic and compositional diversity of fleas parasitic on small mammals and asked whether these patterns are affected by environmental variation or evolutionary/historical processes. We considered environmental variation via both off‐host (air temperature, precipitation, the amount of green vegetation, latitude) and host‐associated (phylogenetic and species composition) environments. The indicators of evolutionary/historical processes were phylogenetic and compositional uniqueness estimated via phylogenetic or compositional, respectively, β‐diversity of either fleas or hosts. We found that phylogenetic uniqueness of flea assemblages was the main predictor of their phylogenetic diversity in all realms. In addition, host phylogenetic diversity and uniqueness played also some role in the Palearctic, whereas the effect of the off‐host environment was either extremely weak or absent. Compositional diversity of fleas was consistently affected by compositional diversity of hosts in all realms except the Neotropics. The effect of the off‐host environment on compositional flea diversity was substantial in all realms except the Palearctic. No effect of latitude on either metric of flea diversity was found. We conclude that phylogenetic diversity of fleas is driven mainly by evolutionary/historical processes, whereas drivers of their compositional diversity are associated with current ecological conditions. 相似文献
84.
85.
Jessica R. Parker Alexander N. Klishko Boris I. Prilutsky Gennady S. Cymbalyuk 《PLoS computational biology》2021,17(12)
Mutually inhibitory populations of neurons, half-center oscillators (HCOs), are commonly involved in the dynamics of the central pattern generators (CPGs) driving various rhythmic movements. Previously, we developed a multifunctional, multistable symmetric HCO model which produced slow locomotor-like and fast paw-shake-like activity patterns. Here, we describe asymmetric features of paw-shake responses in a symmetric HCO model and test these predictions experimentally. We considered bursting properties of the two model half-centers during transient paw-shake-like responses to short perturbations during locomotor-like activity. We found that when a current pulse was applied during the spiking phase of one half-center, let’s call it #1, the consecutive burst durations (BDs) of that half-center increased throughout the paw-shake response, while BDs of the other half-center, let’s call it #2, only changed slightly. In contrast, the consecutive interburst intervals (IBIs) of half-center #1 changed little, while IBIs of half-center #2 increased. We demonstrated that this asymmetry between the half-centers depends on the phase of the locomotor-like rhythm at which the perturbation was applied. We suggest that the fast transient response reflects functional asymmetries of slow processes that underly the locomotor-like pattern; e.g., asymmetric levels of inactivation across the two half-centers for a slowly inactivating inward current. We compared model results with those of in-vivo paw-shake responses evoked in locomoting cats and found similar asymmetries. Electromyographic (EMG) BDs of anterior hindlimb muscles with flexor-related activity increased in consecutive paw-shake cycles, while BD of posterior muscles with extensor-related activity did not change, and vice versa for IBIs of anterior flexors and posterior extensors. We conclude that EMG activity patterns during paw-shaking are consistent with the proposed mechanism producing transient paw-shake-like bursting patterns found in our multistable HCO model. We suggest that the described asymmetry of paw-shaking responses could implicate a multifunctional CPG controlling both locomotion and paw-shaking. 相似文献
86.
87.
88.
Andrew M Jobbins Nejc Haberman Natalia Artigas Christopher Amourda Helen A B Paterson Sijia Yu Samuel J I Blackford Alex Montoya Marian Dore Yi-Fang Wang Alessandro Sardini Inês Cebola Johannes Zuber Sheikh
Tamir Rashid Boris Lenhard Santiago Vernia 《Nucleic acids research》2022,50(6):3379
Pre-mRNA processing is an essential mechanism for the generation of mature mRNA and the regulation of gene expression in eukaryotic cells. While defects in pre-mRNA processing have been implicated in a number of diseases their involvement in metabolic pathologies is still unclear. Here, we show that both alternative splicing and alternative polyadenylation, two major steps in pre-mRNA processing, are significantly altered in non-alcoholic fatty liver disease (NAFLD). Moreover, we find that Serine and Arginine Rich Splicing Factor 10 (SRSF10) binding is enriched adjacent to consensus polyadenylation motifs and its expression is significantly decreased in NAFLD, suggesting a role mediating pre-mRNA dysregulation in this condition. Consistently, inactivation of SRSF10 in mouse and human hepatocytes in vitro, and in mouse liver in vivo, was found to dysregulate polyadenylation of key metabolic genes such as peroxisome proliferator-activated receptor alpha (PPARA) and exacerbate diet-induced metabolic dysfunction. Collectively our work implicates dysregulated pre-mRNA polyadenylation in obesity-induced liver disease and uncovers a novel role for SRSF10 in this process. 相似文献
89.
90.
Loss of S100A9 (MRP14) results in reduced interleukin-8-induced CD11b surface expression,a polarized microfilament system,and diminished responsiveness to chemoattractants in vitro 总被引:1,自引:0,他引:1 下载免费PDF全文
Manitz MP Horst B Seeliger S Strey A Skryabin BV Gunzer M Frings W Schönlau F Roth J Sorg C Nacken W 《Molecular and cellular biology》2003,23(3):1034-1043
The S100A9 (MRP14) protein is abundantly expressed in myeloid cells and has been associated with various inflammatory diseases. The S100A9-deficient mice described here were viable, fertile, and generally of healthy appearance. The myelopoietic potential of the S100A9-null bone marrow was normal. S100A8, the heterodimerization partner of S100A9 was not detectable in peripheral blood cells, suggesting that even a deficiency in both S100A8 and S100A9 proteins was compatible with viable and mature neutrophils. Surprisingly, the invasion of S100A9-deficient leukocytes into the peritoneum and into the skin in vivo was indistinguishable from that in wild-type mice. However, stimulation of S100A9-deficient neutrophils with interleukin-8 in vitro failed to provoke an up-regulation of CD11b. Migration upon a chemotactic stimulus through an endothelial monolayer was markedly diminished in S100A9-deficient neutrophils. Attenuated chemokinesis of the S100A9-deficient neutrophils was observed by using a three-dimensional collagen matrix migration assay. The altered migratory behavior was associated with a microfilament system that was highly polarized in unstimulated S100A9-deficient neutrophils. Our data suggest that loss of the calcium-binding S100A9 protein reduces the responsiveness of the neutrophils upon chemoattractant stimuli at least in vitro. Alternative pathways for neutrophil emigration may be responsible for the lack of any effect in the two in vivo models we have investigated so far. 相似文献