全文获取类型
收费全文 | 3193篇 |
免费 | 167篇 |
国内免费 | 23篇 |
专业分类
化学 | 2268篇 |
晶体学 | 17篇 |
力学 | 175篇 |
数学 | 500篇 |
物理学 | 423篇 |
出版年
2024年 | 5篇 |
2023年 | 26篇 |
2022年 | 36篇 |
2021年 | 62篇 |
2020年 | 78篇 |
2019年 | 67篇 |
2018年 | 49篇 |
2017年 | 35篇 |
2016年 | 102篇 |
2015年 | 101篇 |
2014年 | 137篇 |
2013年 | 167篇 |
2012年 | 280篇 |
2011年 | 285篇 |
2010年 | 179篇 |
2009年 | 148篇 |
2008年 | 213篇 |
2007年 | 205篇 |
2006年 | 179篇 |
2005年 | 157篇 |
2004年 | 157篇 |
2003年 | 141篇 |
2002年 | 148篇 |
2001年 | 43篇 |
2000年 | 41篇 |
1999年 | 37篇 |
1998年 | 17篇 |
1997年 | 29篇 |
1996年 | 32篇 |
1995年 | 20篇 |
1994年 | 18篇 |
1993年 | 16篇 |
1992年 | 15篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1968年 | 15篇 |
1967年 | 9篇 |
排序方式: 共有3383条查询结果,搜索用时 29 毫秒
991.
Electrochemical methods provide a wide range of strategies to explore the metabolism of drugs. These approaches traditionally encompass preparative aspects viz. the electrochemical generation of potent metabolites or the electrochemical exploration of the reactivity of redox enzymes (or their mimics) toward drugs. More recently, the electroanalytical characterization of the successive redox and redox-coupled reactions was found effective to unravel more complex mechanisms, especially those related to the reactivity of bioorganometallic drugs. This minireview highlights the contribution of these different electrochemical strategies to the determination of drug metabolism through representative recent examples. 相似文献
992.
Theoretical and experimental characterization of amino‐PEG‐phosphonate‐terminated Polyphosphorhydrazone dendrimers: Influence of size and PEG capping on cytotoxicity profiles 下载免费PDF全文
Aurélien Hameau Séverine Fruchon Christian Bijani Alessandro Barducci Muriel Blanzat Rémy Poupot Giovanni M. Pavan Anne‐Marie Caminade Cédric‐Olivier Turrin 《Journal of polymer science. Part A, Polymer chemistry》2015,53(6):761-774
The synthesis of new series of PPH (poly(phosphorhydrazone)) dendrimers with amino‐PEG phosphonates or the corresponding amino‐PEG phosphonic acids as terminal groups is presented, from generations 1–3. The size of PEG‐terminated dendrimers is experimentally measured by diffusional NMR, and by means of dynamic light scattering. Classical molecular dynamics and well‐tempered metadynamics simulations are used to assess or confirm the formation of aggregates in some cases. The influence of PEG capping on the cytotoxicity profiles of the dendrimers is evaluated on human peripheral blood mononuclear cells by means of LIVE/DEAD assays, and confirms the importance of PEG capping to ensure low cytotoxicity. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 761–774 相似文献
993.
We introduce the cluster index of a multivariate stationary sequence and characterize the index in terms of the spectral tail process. This index plays a major role in limit theory for partial sums of sequences. We illustrate the use of the cluster index by characterizing infinite variance stable limit distributions and precise large deviation results for sums of multivariate functions acting on a stationary Markov chain under a drift condition. 相似文献
994.
Alain Rolland Laurent Pedesseau Jacky Even Samy Almosni Cedric Robert Charles Cornet Jean Marc Jancu Jamal Benhlal Olivier Durand Alain Le Corre Pierre Rale Laurent Lombez Jean-Francois Guillemoles Eric Tea Sana Laribi 《Optical and Quantum Electronics》2014,46(10):1397-1403
In this paper, we present a comprehensive study of high efficiencies tandem solar cells monolithically grown on a silicon substrate using GaAsPN absorber layer. InGaAs(N) quantum dots and GaAsPN quantum wells have been grown recently on GaP/Si susbstrate for applications related to light emission. For photovoltaic applications, we consider the GaAsPN diluted nitride alloy as the top junction material due to both its perfect lattice matching with Si and ideal bandgap energy for current generation in association with the Si bottom cell. Numerical simulation of the top cell is performed. The effect of layer thicknesses and doping on the cell efficiency are evidenced. In these structures a tunnel junction (TJ) is needed to interconnect both the top and bottom sub-cells. We compare the simulated performances of different TJ structures and show that the GaP(n+)/Si(p+) TJ is promising to improve performances of the current–voltage characteristic. 相似文献
995.
996.
A wide range of diffractive elements have been used to evaluate the topological charge of Laguerre–Gaussian beams. Here, we show theoretically and experimentally that this charge can be simply and readily measured from the interference pattern in Young’s double-slit experiment. It can be evaluated from the twisting order of the interference. The results are confronted with previously published studies. The potentialities of the method are then compared with existing techniques. 相似文献
997.
998.
Inhibition of Cu‐Amyloid‐β by using Bifunctional Peptides with β‐Sheet Breaker and Chelator Moieties
999.
We consider scattering of a pulse propagating through a three-dimensional random media and study the shape of the pulse in the parabolic approximation. We show that, similarly to the one-dimensional O’Doherty–Anstey theory, the pulse undergoes a deterministic broadening. Its amplitude decays only algebraically and not exponentially in time, due to the signal low/midrange frequency component. We also argue that the parabolic approximation captures the front evolution (but not the signal away from the front) correctly even in the fully three-dimensional situation. 相似文献
1000.