全文获取类型
收费全文 | 505篇 |
免费 | 34篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 12篇 |
妇产科学 | 2篇 |
基础医学 | 74篇 |
口腔科学 | 13篇 |
临床医学 | 42篇 |
内科学 | 106篇 |
神经病学 | 42篇 |
特种医学 | 8篇 |
外科学 | 147篇 |
预防医学 | 13篇 |
药学 | 34篇 |
肿瘤学 | 45篇 |
出版年
2023年 | 5篇 |
2022年 | 14篇 |
2021年 | 20篇 |
2020年 | 12篇 |
2019年 | 13篇 |
2018年 | 14篇 |
2017年 | 5篇 |
2016年 | 18篇 |
2015年 | 19篇 |
2014年 | 26篇 |
2013年 | 32篇 |
2012年 | 39篇 |
2011年 | 53篇 |
2010年 | 28篇 |
2009年 | 26篇 |
2008年 | 34篇 |
2007年 | 20篇 |
2006年 | 25篇 |
2005年 | 29篇 |
2004年 | 21篇 |
2003年 | 18篇 |
2002年 | 22篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1964年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有539条查询结果,搜索用时 796 毫秒
1.
2.
3.
4.
Saghatelyan AK Gorissen S Albert M Hertlein B Schachner M Dityatev A 《The European journal of neuroscience》2000,12(9):3331-3342
Perisomatic inhibition of pyramidal cells regulates efferent signalling from the hippocampus. The striking presence of HNK-1, a carbohydrate expressed by neural adhesion molecules, on perisomatic interneurons and around somata of CA1 pyramidal neurons led us to apply monoclonal HNK-1 antibodies to acute murine hippocampal slices. Injection of these antibodies decreased GABAA receptor-mediated perisomatic inhibitory postsynaptic currents (pIPSCs) but did not affect dendritic IPSCs or excitatory postsynaptic currents. The decrease in the mean amplitude of evoked pIPSCs by HNK-1 antibodies was accompanied by an increase in the coefficient of variation of pIPSC amplitude, number of failures and changes in frequency but not amplitude of miniature IPSCs, suggesting that HNK-1 antibodies reduced efficacy of evoked GABA release. HNK-1 antibodies did not affect pIPSCs in knock-out mice deficient in the extracellular matrix molecule tenascin-R which carries the HNK-1 carbohydrate as analysed by immunoblotting in synaptosomal fractions prepared from the CA1 region of the hippocampus. For control, HNK-1 antibody was applied to acute sections of mice deficient in the neural cell adhesion molecule NCAM, another potential carrier of HNK-1, and resulted in decrease of pIPSCs as observed in wild-type mice. Reduction in perisomatic inhibition is expected to promote induction of long-term potentiation (LTP) by increasing the level of depolarization during theta-burst stimulation. Indeed, LTP was increased by HNK-1 antibody applied before stimulation. Moreover, LTP was reduced by an HNK-1 peptide mimic, but not control peptide. These results provide first evidence that tenascin-R and its associated HNK-1 carbohydrate modulate perisomatic inhibition and synaptic plasticity in the hippocampus. 相似文献
5.
Sharon S. Stanley Ernesto P. Molmenti Eric Siskind Armen K. Kasabian Su-I D. Huang 《The International journal of angiology》2014,23(1):61-64
The Morel-Lavallee lesion is a closed, internal degloving injury that results when a strong, shearing force is applied parallel to the plane of injury, as is common in vehicular trauma. It is an underdiagnosed entity that is often missed during the initial trauma workup as symptoms can be subtle. There are few reports of lesions occurring below the knee. Most cases affect the proximal thigh and trochanter, as these tend to be dependent areas in high velocity trauma. To the best of our knowledge, this is the first literature report of bilateral lower extremity Morel-Lavallee lesions. 相似文献
6.
Characterization of a possible amyloidogenic precursor in glutamine-repeat neurodegenerative diseases
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Armen RS Bernard BM Day R Alonso DO Daggett V 《Proceedings of the National Academy of Sciences of the United States of America》2005,102(38):13433-13438
Several neurodegenerative diseases are linked to expanded repeats of glutamine residues, which lead to the formation of amyloid fibrils and neuronal death. The length of the repeats correlates with the onset of Huntington's disease, such that healthy individuals have <38 residues and individuals with >38 repeats exhibit symptoms. Because it is difficult to obtain atomic-resolution structural information for poly(l-glutamine) (polyQ) in aqueous solution experimentally, we performed molecular dynamics simulations to investigate the conformational behavior of this homopolymer. In simulations of 20-, 40-, and 80-mer polyQ, we observed the formation of the "alpha-extended chain" conformation, which is characterized by alternating residues in the alpha(L) and alpha(R) conformations to yield a sheet. The structural transition from disordered random-coil conformations to the alpha-extended chain conformation exhibits modest length and temperature dependence, in agreement with the experimental observation that aggregation depends on length and temperature. We propose that fibril formation in polyQ may occur through an alpha-sheet structure, which was proposed by Pauling and Corey. Also, we propose an atomic-resolution model of how the inhibitory peptide QBP1 (polyQ-binding peptide 1) may bind to polyQ in an alpha-extended chain conformation to inhibit fibril formation. 相似文献
7.
John B. Little U. Ingrid Richardson Armen H. Tashjian Jr. 《Proceedings of the National Academy of Sciences of the United States of America》1972,69(6):1363-1365
The radiosensitivities of a strain of mouse fibroblasts (Cl-1D), of rat pituitary cells (GH(1)2C(1)), and of a hybrid between the two (alpha-RST) have been studied. Their mean chromosome numbers were 50, 70, and 111, respectively. The hybrid cells were much more resistent to radiation than either of the parent strains. The range of the D(0) (reciprocal of the slope, and therefore a measure of radiosensitivity) for the linear portion of the survival curves for each cell line was: Cl-1D, 134-142 R; GH(1)2C(1), 154-170 R; and alpha-RST, 248-274 R. There were no significant differences in the magnitude of the shoulder or extrapolation number of the survival curves, nor in the ability of the three cell strains to accumulate and repair sublethal radiation damage. It appears unlikely that the unusual resistance of the hybrid strain is simply related to the increase in chromosome number; more likely, it involves some interaction between the two genomes. The study of somatic cell hybrids may offer further insight into the factors controlling the radiosensitivity of mammalian cells. 相似文献
8.
9.
10.