全文获取类型
收费全文 | 4997篇 |
免费 | 746篇 |
国内免费 | 477篇 |
专业分类
化学 | 2159篇 |
晶体学 | 84篇 |
力学 | 1229篇 |
综合类 | 53篇 |
数学 | 733篇 |
物理学 | 1962篇 |
出版年
2023年 | 56篇 |
2022年 | 100篇 |
2021年 | 131篇 |
2020年 | 180篇 |
2019年 | 292篇 |
2018年 | 158篇 |
2017年 | 191篇 |
2016年 | 212篇 |
2015年 | 170篇 |
2014年 | 198篇 |
2013年 | 369篇 |
2012年 | 208篇 |
2011年 | 270篇 |
2010年 | 197篇 |
2009年 | 286篇 |
2008年 | 276篇 |
2007年 | 295篇 |
2006年 | 267篇 |
2005年 | 231篇 |
2004年 | 241篇 |
2003年 | 214篇 |
2002年 | 214篇 |
2001年 | 166篇 |
2000年 | 142篇 |
1999年 | 138篇 |
1998年 | 120篇 |
1997年 | 101篇 |
1996年 | 80篇 |
1995年 | 93篇 |
1994年 | 66篇 |
1993年 | 51篇 |
1992年 | 44篇 |
1991年 | 34篇 |
1990年 | 42篇 |
1989年 | 39篇 |
1988年 | 29篇 |
1987年 | 16篇 |
1986年 | 17篇 |
1985年 | 23篇 |
1984年 | 29篇 |
1982年 | 32篇 |
1981年 | 23篇 |
1980年 | 16篇 |
1979年 | 37篇 |
1978年 | 15篇 |
1977年 | 23篇 |
1976年 | 14篇 |
1975年 | 15篇 |
1974年 | 16篇 |
1973年 | 19篇 |
排序方式: 共有6220条查询结果,搜索用时 203 毫秒
1.
《Progress in Surface Science》2022,97(3):100663
High-reflective multilayer laser coatings are widely used in advanced optical systems from high power laser facilities to high precision metrology systems. However, the real interface quality and defects will significantly affect absorption/scattering losses and laser induced damage thresholds of multilayer coatings. With the recent advances in the control of coating design and deposition processes, these coating properties can be significantly improved when properly engineered the interface and defects. This paper reviews the recent progress in the physics of laser damage, optical losses and environmental stability involved in multilayer reflective coatings for high power nanosecond near-infrared lasers. We first provide an overview of the layer growth mechanisms, ways to control the microstructures and reduce layer roughness, as well as the nature of defects which are critical to the optical loss and laser induced damage. Then an overview of interface engineering based on the design of coating structure and the regulation of deposition materials reveals their ability to improve the laser induced damage threshold, reduce the backscattering, and realize the desirable properties of environmental stability and exceptional multifunctionality. Moreover, we describe the recent progress in the laser damage and scattering mechanism of nodule defects and give the approaches to suppress the defect-induced damage and scattering of the multilayer laser coatings. Finally, the present challenges and limitations of high-performance multilayer laser coatings are highlighted, along with the comments on likely trends in future. 相似文献
2.
In this work, a continuum model is presented for size and orientation dependent thermal buckling and post-buckling of anisotropic nanoplates considering surface and bulk residual stresses. The model with von-Karman nonlinear strains and material cubic anisotropy of single crystals contains two parameters that reflect the orientation effects. Using Ritz method, closed form solutions are given for buckling temperature and post-buckling deflections. Regarding self-instability states of nanoplates and their recovering at higher temperatures, an experiment is discussed based on low pressurized membranes to verify the predictions. For simply supported nanoplates, the size effects are lowest when they are aligned in [100] direction. When the edges get clamped, the orientation dependence is ignorable and the behavior becomes symmetric about [510] axis. The surface residual stress makes drastic increase in buckling temperature of thinner nanoplates for which a minimum thickness is pointed to stay far from material softening at higher temperatures. Deflection of [100]-oriented buckled nanoplates is higher than [110] ones but this reverses at higher temperatures. The results for long nanoplates show that the buckling mode numbers are changed by orientation which is verified by FEM. 相似文献
3.
Self-assembly is a versatile bottom-up approach for fabricating novel supramolecular materials with well-defined nano- or micro-structures associated with functionalities. The oil-water interface provides an ideal venue for molecular and colloidal self-assembly. This paper gives an overview of various self-assembled materials, including nanoparticles, polymers, proteins, and lipids, at the oil-water interface. Focus has been given to fundamental principles and strategies for engineering the self-assembly process, such as control of pH, ionic strength and use of external fields, to achieve complex soft materials with desired functionalities, such as nanoparticle surfactants, structured liquids, and proteinosomes. It has been shown that self-assembly at the oil-water interface holds great promise for developing well-structured complex materials useful for many research and industrial applications. 相似文献
4.
5.
固体间界面的物理模型和界面对声波的反射 总被引:4,自引:0,他引:4
简要描述了模拟两固体间界面特性的弹簧模型,该模型最早是根据静力学方法提出的,后来用固体间界面薄层的声波反射方法加以改进,从界面弹簧模型可以方便地得到界面外近似边界条件,其中包含界面“弹簧”振子的劲度常数和质量,文章还给出了两相间固体中界面声反射系数的表达式,介绍了测量界面劲度常数的超声反射谱方法。最后讨论了仍关声波与界面相互作用研究领域中最近的一些研究进展。 相似文献
6.
Alexander Krasnosel'skii Dmitrii Rachinskii 《NoDEA : Nonlinear Differential Equations and Applications》2002,9(1):93-115
We consider autonomous systems with a nonlinear part depending on a parameter and study Hopf bifurcations at infinity. The
nonlinear part consists of the nonlinear functional term and the Prandtl--Ishlinskii hysteresis term. The linear part of the
system has a special form such that the close-loop system can be considered as a hysteresis perturbation of a quasilinear
Hamiltonian system. The Hamiltonian system has a continuum of arbitrarily large cycles for each value of the parameter. We
present sufficient conditions for the existence of bifurcation points for the non-Hamiltonian system with hysteresis. These
bifurcation points are determined by simple characteristics of the hysteresis nonlinearity. 相似文献
7.
8.
A simple simulation scheme that simultaneously describes the growth kinetics of SiO2 films at the nanometer scale and the SiOx/Si interface dynamics (its extent, and spatial/temporal evolution) is presented. The simulation successfully applies to experimental data in the region above and below 10 nm, reproduces the Deal and Grove linear-parabolic law and the oxide growth rate enhancement in the very thin film regime (the so-called anomalous region). According to the simulation, the oxidation is governed mainly by two processes: (a) the formation of a transition suboxide layer and (b) its subsequent drift towards the silicon bulk. We found that it is the superposition of these two processes that produces the crossover from the anomalous oxidation region behavior to the linear-parabolic law. 相似文献
9.
10.
High temperature oxidation of metals leads to residual stresses both in the metal and in the growing oxide. In this work, the evolution of this residual stresses is theoretically predicted in the growing oxide layers. The origin of these stresses is based on a microstructural model. Using experimental results providing from the oxidation kinetics, and an analysis proposed to describe the growth strain occurring in the thin layers, a set of equations is established allowing determining the stresses evolution with oxidation time. Then, the model is compared with experimental results obtained on both α-Fe and phosphated α-Fe, oxidised at different temperatures. Numerical data are extracted from experiments either with an asymptotic formulation or with an inverse method. These two methods give good agreement with experiments and allow extracting the model parameters. 相似文献