全文获取类型
收费全文 | 939篇 |
免费 | 46篇 |
国内免费 | 7篇 |
专业分类
化学 | 658篇 |
力学 | 22篇 |
数学 | 159篇 |
物理学 | 153篇 |
出版年
2023年 | 17篇 |
2022年 | 9篇 |
2021年 | 33篇 |
2020年 | 25篇 |
2019年 | 27篇 |
2018年 | 10篇 |
2017年 | 12篇 |
2016年 | 38篇 |
2015年 | 36篇 |
2014年 | 39篇 |
2013年 | 63篇 |
2012年 | 61篇 |
2011年 | 66篇 |
2010年 | 35篇 |
2009年 | 43篇 |
2008年 | 39篇 |
2007年 | 55篇 |
2006年 | 37篇 |
2005年 | 45篇 |
2004年 | 37篇 |
2003年 | 25篇 |
2002年 | 26篇 |
2001年 | 12篇 |
2000年 | 3篇 |
1999年 | 16篇 |
1998年 | 10篇 |
1997年 | 11篇 |
1996年 | 13篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 12篇 |
1985年 | 8篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1980年 | 10篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1972年 | 6篇 |
1971年 | 4篇 |
1936年 | 2篇 |
1930年 | 2篇 |
排序方式: 共有992条查询结果,搜索用时 250 毫秒
191.
The determination of the theoretically introduced material parameters is always a big issue, especially in computational biomechanics. In this context it is difficult to obtain the appropriate intervertebral disc (IVD) specimens within 24 h post decease and to perform reliable experiments on them, respectively. A complex test setup is needed for most of the cases and the measured results are very ‘patient specific’. On the other hand, the parameters obtained from literature are often also not reliable, because they are widespread, the experimental setup is not clearly described or was deficient. Moreover, as soft tissues generally exhibit a coupled dissipative behaviour, it is often not possible to measure these effects independently. Hence, the parameters have to be identified by inverse computations, i. e., axial compression, bending or torsion of a whole motion segment. The goal of this contribution is to proceed from an extended biphasic model and a set of suitable material parameters obtained from literature, in order to find the influence of certain parameters on a numerical compression-bending experiment of a L4-L5 motion segment. Finally, a comment on how the respective parameters should be determined is given. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
192.
The self-assembly of discrete molecular entities into functional nanomaterials has become a major research area in the past decades. The library of investigated compounds has diversified significantly, while the field as a whole has matured. The incorporation of metal ions in the molecular design of the (supra-)molecular building blocks greatly expands the potential applications, while also offering a promising approach to control molecular recognition and attractive and/or repulsive intermolecular binding events. Hence, supramolecular polymerization of metal-containing monomers has emerged as a major research focus in the field. In this perspective article, we highlight recent significant advances in supramolecular polymerization of metal-containing monomers and discuss their implications for future research. Additionally, we also outline some major challenges that metallosupramolecular chemists (will) have to face to produce metallosupramolecular polymers (MSPs) with advanced applications and functionalities.In this perspective article, we highlight recent significant advances in the self-assembly of metal-containing monomers and discuss their implications for future research. 相似文献
193.
Christine N. Morrison Kathleen E. Prosser Ryjul W. Stokes Anna Cordes Nils Metzler-Nolte Seth M. Cohen 《Chemical science》2022,13(32):9450
Correction for ‘Expanding medicinal chemistry into 3D space: metallofragments as 3D scaffolds for fragment-based drug discovery’ by Christine N. Morrison et al., Chem. Sci., 2020, 11, 1216–1225, https://doi.org/10.1039/C9SC05586J.The authors regret that in the original article, inhibitory values reported for some metallofragments were incorrect. Unfortunately, DMSO stock solutions of reportedly active ferrocene-based metallofragments were found to decompose in the presence of light, which resulted in inaccurate inhibition values. The authors maintain that the core conclusions of the paper are accurate and the utility of three-dimensional metal complexes for fragment-based drug discovery has merit.In the original article, ‘class A’ metallofragments are comprised of ferrocene derivatives (Fig. 1). Some of these ferrocene fragments (specifically those containing carbonyl groups) are reported as broadly inhibiting several protein targets. It was noted in our original report that the ferrocene scaffold was likely promiscuous due to its lipophilicity and potential redox activity, but that it might still serve as a useful metallofragment for fragment-based drug discovery (FBDD) campaigns. However, re-evaluation of these compounds against the influenza endonuclease (PAN) failed to reproduce our original inhibition results for the class A metallofragments using freshly prepared stocks, indicating a problem with the materials used in the original study.Open in a separate windowFig. 1Chemical structures of class A metallofragments.Several compounds from class A were originally reported as having near complete (100%) inhibition against PAN endonuclease at an inhibitor concentration of 200 μM (and2).2). However, when re-evaluated under identical conditions, using freshly prepared DMSO stock solutions, inhibition was only observed with one fragment of this class (A22, Fig. 1), with the previously reported highly active fragments (A4, A7–A21, Compound A1 A2 A3 A4 A5 A7 A8 A9 A10 A11 Reported 12 ± 6 <1 <1 45 ± 14 8 ± 7 103 ± 5 103 ± 4 53 ± 5 46 ± 7 90 ± 5 Corrected 3 ± 10 n.d. 18 ± 3 6 ± 3 21 ± 5 9 ± 3 10 ± 5 4 ± 2 16 ± 4 10 ± 7