全文获取类型
收费全文 | 203775篇 |
免费 | 16051篇 |
国内免费 | 8912篇 |
出版年
2023年 | 1341篇 |
2022年 | 3255篇 |
2021年 | 6297篇 |
2020年 | 4335篇 |
2019年 | 5364篇 |
2018年 | 5716篇 |
2017年 | 4441篇 |
2016年 | 6203篇 |
2015年 | 8367篇 |
2014年 | 9879篇 |
2013年 | 11210篇 |
2012年 | 13159篇 |
2011年 | 12256篇 |
2010年 | 8000篇 |
2009年 | 7049篇 |
2008年 | 8714篇 |
2007年 | 8100篇 |
2006年 | 7246篇 |
2005年 | 6126篇 |
2004年 | 5598篇 |
2003年 | 5231篇 |
2002年 | 4616篇 |
2001年 | 6231篇 |
2000年 | 5815篇 |
1999年 | 4874篇 |
1998年 | 2071篇 |
1997年 | 2026篇 |
1996年 | 1853篇 |
1995年 | 1645篇 |
1994年 | 1609篇 |
1993年 | 1443篇 |
1992年 | 3249篇 |
1991年 | 3063篇 |
1990年 | 2920篇 |
1989年 | 2640篇 |
1988年 | 2415篇 |
1987年 | 2316篇 |
1986年 | 2090篇 |
1985年 | 2103篇 |
1984年 | 1648篇 |
1983年 | 1456篇 |
1982年 | 1027篇 |
1979年 | 1512篇 |
1978年 | 1174篇 |
1977年 | 1074篇 |
1975年 | 1212篇 |
1974年 | 1305篇 |
1973年 | 1393篇 |
1972年 | 1231篇 |
1971年 | 1061篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
141.
142.
Peng Wang Ronghua Luo Min Zhang Yaqing Wang Tianzhang Song Tingting Tao Zhongyu Li Lin Jin Hongyi Zheng Wenwen Chen Mengqian Zhao Yongtang Zheng Jianhua Qin 《Cell death & disease》2020,11(12)
COVID-19, caused by SARS-CoV-2, is an acute and rapidly developing pandemic, which leads to a global health crisis. SARS-CoV-2 primarily attacks human alveoli and causes severe lung infection and damage. To better understand the molecular basis of this disease, we sought to characterize the responses of alveolar epithelium and its adjacent microvascular endothelium to viral infection under a co-culture system. SARS-CoV-2 infection caused massive virus replication and dramatic organelles remodeling in alveolar epithelial cells, alone. While, viral infection affected endothelial cells in an indirect manner, which was mediated by infected alveolar epithelium. Proteomics analysis and TEM examinations showed viral infection caused global proteomic modulations and marked ultrastructural changes in both epithelial cells and endothelial cells under the co-culture system. In particular, viral infection elicited global protein changes and structural reorganizations across many sub-cellular compartments in epithelial cells. Among the affected organelles, mitochondrion seems to be a primary target organelle. Besides, according to EM and proteomic results, we identified Daurisoline, a potent autophagy inhibitor, could inhibit virus replication effectively in host cells. Collectively, our study revealed an unrecognized cross-talk between epithelium and endothelium, which contributed to alveolar–capillary injury during SARS-CoV-2 infection. These new findings will expand our understanding of COVID-19 and may also be helpful for targeted drug development.Subject terms: Mechanisms of disease, Viral infection 相似文献
143.
144.
145.
146.
147.
The perfusion procedure described in this paper produces high quality impregnation of pig visual and somatosensory cortical neurons with a Golgi-Cox solution. Starting within 30 min after death, pig heads were perfused with a fixative solution composed of a mixture (v/v) of liquid phenol, 5%; formalin, 14%; ethylene glycol, 25%; methanol, 28%; and water, 28% for two periods of 4 hr each. After perfusion, the heads were chilled for at least 18 hr. The entire brain was removed from the skull and then placed in 10% buffered formalin, where it remained for at least 10 days before taking the blocks that were to be immersed in the Golgi-Cox solution. Three weeks spent in the Golgi-Cox solution typically produced uniform neuron impregnation. The tissue blocks were then embedded in celloidin and sectioned at 120 micron. This procedure avoids the following difficulties: Golgi-Cox methods that produced excellent results with rodent or primate tissue were unsuccessful with pig tissue, placing fresh tissue in Golgi-Cox solution resulted in incomplete neuron impregnation, and immersion fixation in 10% buffered formalin without perfusion resulted in excessive staining of glia. 相似文献
148.
149.
150.
Molecular dynamics (MD) simulations of phosphatidylinositol (4,5)-bisphosphate (PIP2) and phosphatidylinositol (3,4,5)-trisphosphate (PIP3) in 1-palmitoyl 2-oleoyl phosphatidylcholine (POPC) bilayers indicate that the inositol rings are tilted ∼40° with respect to the bilayer surface, as compared with 17° for the P-N vector of POPC. Multiple minima were obtained for the ring twist (analogous to roll for an airplane). The phosphates at position 1 of PIP2 and PIP3 are within an Ångström of the plane formed by the phosphates of POPC; lipids in the surrounding shell are depressed by 0.5-0.8 Å, but otherwise the phosphoinositides do not substantially perturb the bilayer. Finite size artifacts for ion distributions are apparent for systems of ∼26 waters/lipid, but, based on simulations with a fourfold increase of the aqueous phase, the phosphoinositide positions and orientations do not show significant size effects. Electrostatic potentials evaluated from Poisson-Boltzmann (PB) calculations show a strong dependence of potential height and ring orientation, with the maxima on the −25 mV surfaces (17.1 ± 0.1 Å for PIP2 and 19.4 ± 0.3 Å for PIP3) occurring near the most populated orientations from MD. These surfaces are well above the background height of 10 Å estimated for negatively charged cell membranes, as would be expected for lipids involved in cellular signaling. PB calculations on microscopically flat bilayers yield similar maxima as the MD-based (microscopically rough) systems, but show less fine structure and do not clearly indicate the most probable regions. Electrostatic free energies of interaction with pentalysine are also similar for the rough and flat systems. These results support the utility of a rigid/flat bilayer model for PB-based studies of PIP2 and PIP3 as long as the orientations are judiciously chosen. 相似文献