全文获取类型
收费全文 | 2586篇 |
免费 | 62篇 |
国内免费 | 9篇 |
专业分类
化学 | 1652篇 |
晶体学 | 42篇 |
力学 | 89篇 |
数学 | 595篇 |
物理学 | 279篇 |
出版年
2023年 | 15篇 |
2022年 | 47篇 |
2021年 | 68篇 |
2020年 | 42篇 |
2019年 | 44篇 |
2018年 | 32篇 |
2017年 | 24篇 |
2016年 | 65篇 |
2015年 | 70篇 |
2014年 | 57篇 |
2013年 | 133篇 |
2012年 | 111篇 |
2011年 | 157篇 |
2010年 | 98篇 |
2009年 | 89篇 |
2008年 | 129篇 |
2007年 | 109篇 |
2006年 | 142篇 |
2005年 | 127篇 |
2004年 | 110篇 |
2003年 | 94篇 |
2002年 | 80篇 |
2001年 | 31篇 |
2000年 | 17篇 |
1999年 | 28篇 |
1998年 | 23篇 |
1997年 | 24篇 |
1996年 | 42篇 |
1995年 | 27篇 |
1994年 | 32篇 |
1993年 | 26篇 |
1992年 | 20篇 |
1991年 | 21篇 |
1990年 | 22篇 |
1989年 | 12篇 |
1988年 | 17篇 |
1987年 | 16篇 |
1986年 | 12篇 |
1985年 | 30篇 |
1984年 | 15篇 |
1983年 | 19篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 33篇 |
1979年 | 31篇 |
1978年 | 18篇 |
1977年 | 12篇 |
1976年 | 16篇 |
1975年 | 13篇 |
1915年 | 9篇 |
排序方式: 共有2657条查询结果,搜索用时 31 毫秒
1.
2.
Functional Binding Surface of a β‐Hairpin VEGF Receptor Targeting Peptide Determined by NMR Spectroscopy in Living Cells
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Donatella Diana Anna Russomanno Dr. Lucia De Rosa Dr. Rossella Di Stasi Dr. Domenica Capasso Dr. Sonia Di Gaetano Dr. Alessandra Romanelli Dr. Luigi Russo Dr. Luca D. D'Andrea Prof. Roberto Fattorusso 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(1):91-95
In this study, the functional interaction of HPLW peptide with VEGFR2 (Vascular Endothelial Growth Factor Receptor 2) was determined by using fast 15N‐edited NMR spectroscopic experiments. To this aim, 15N uniformly labelled HPLW has been added to Porcine Aortic Endothelial Cells. The acquisition of isotope‐edited NMR spectroscopic experiments, including 15N relaxation measurements, allowed a precise characterization of the in‐cell HPLW epitope recognized by VEGFR2. 相似文献
3.
Vito Gigante Laura Aliotta Maria Beatrice Coltelli Patrizia Cinelli Luigi Botta Francesco Paolo La Mantia Andrea Lazzeri 《Journal of polymer science. Part A, Polymer chemistry》2020,58(23):3264-3282
The development of biodegradable materials for tailored applications, particularly in the field of polymeric films and sheets, is a challenging technological goal as well as a contribution to help protect the environment. Poly(lactic) acid (PLA) is a promising substitute for several oil-based polymers; however, to overcome its thermal and mechanical drawbacks, researchers have developed solutions such as blending PLA with polybutylene adipate terephthalate (PBAT), which is capable of increasing the ductility of the final material. In this study, PLA/PBAT binary blends, with minimum possible content of nonrenewable materials, were examined from processing, thermal, morphological, and rheological perspective. An optimized PLA/PBAT ratio was chosen as the polymeric basis to obtain a biodegradable formulation by adding a biobased plasticizer and appropriate fillers to produce a micrometer film with tailored flexibility and tear resistance. The processing technology involved flat-die extrusion, followed by calendering. The tearing resistance of the produced film was investigated, and the results were compared with literature data. A study on the essential work of fracture was implemented to explore the mode III out-of-plane fracture resistance starting from a trouser tear test. 相似文献
4.
5.
Giuseppe Coppola Andrea Irace Giovanni Breglio Mario Iodice Luigi Zeni Antonello Cutolo Pasqualina M. Sarro 《Optics and Lasers in Engineering》2003,39(3):317-332
In this paper we describe two different kind of optoelectronic devices both based on a three terminals active device and exploit the plasma dispersion effect to achieve the desired working. The first device exploits this effect in order to obtain an optical modulation. The second device is an optoelectronic router based on the mode-mixing principle together with the injection-induced optical phase shift. Both devices are integrated into a Silicon on Silicon optical channel waveguide which can be realized using a standard bipolar process. The possibility of using standard, well-known technology presents several advantages with respect to III–V Optoelectronics. The active three terminal device used is a Bipolar Mode Field Effect Transistor (BMFET). Numerical simulation results are presented on both devices. 相似文献
6.
Giovanni Giachetta Luigi Mangiarotti 《International Journal of Theoretical Physics》1997,36(1):125-141
We consider a metric-affine gravitational framework in which the dynamical fields are the spin structures, the general linear
connections, and the Dirac fermion fields. Using a spin structure and a linear connection on the world manifold, we construct
a principal connection on the spinor bundle. By applying general ideas concerning the conservation laws in the Lagrangian
approach to field theory, we examine the corresponding conserved currents. The main result is that the currents associated
with infinitesimal vertical (internal) transformations of the covariance group are shown to vanish identically. It follows
that to every vector field on the world manifold there corresponds a well-defined current, the stress-energymomentum of the
fields. It turns out that the fermion fields do not contribute at all to the superpotential terms. Actually the expression
we get for the superpotential generalizes the well-known expression obtained by Komar. 相似文献
7.
8.
Telecommunications systems have recently undergone significant innovations. These call for suitable statistical models that can properly describe the behaviour of the input traffic in a network. Here we use fractional Brownian motion (FBM) to model cumulative traffic network, thus taking into account the possible presence of long‐range dependence in the data. A Bayesian approach is devised in such a way that we are able to: (a) estimate the Hurst parameter H of the FBM; (b) estimate the overflow probability which is a parameter measuring the quality of service of a network: (c) develop a test for comparing the null hypothesis of long‐range dependence in the data versus the alternative of short‐range dependence. In order to achieve these inferential results, we elaborate an MCMC sampling scheme whose output enables us to obtain an approximation of the quantities of interest. An application to three real datasets, corresponding to three different levels of traffic, is finally considered. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
9.
The inhomogeneous Gevrey classes, defined in terms of Fourier transform, are a natural extension of the standard Gevrey classes. We find equivalent characterizations and discuss algebraic and topological properties. We therefore introduce the dual spaces, the inhomogeneous ultradistributions, giving some equivalent definitions and corresponding algebraic and topological properties; in particular, a version of the Paley-Wiener-Schwartz theorem is proved in our framework. Finally, as an important example, the multianisotropic Gevrey classes and ultradistributions are considered. 相似文献
10.
We present a new approach, requiring the solution of a SemiDefinite Program, for decomposing the Hessian of a nonseparable mixed-integer quadratic problem to permit using perspective cuts to improve its continuous relaxation bound. The new method favorably compares with a previously proposed one requiring a minimum eigenvalue computation. 相似文献