全文获取类型
收费全文 | 2019篇 |
免费 | 262篇 |
国内免费 | 240篇 |
专业分类
化学 | 1414篇 |
晶体学 | 20篇 |
力学 | 88篇 |
综合类 | 4篇 |
数学 | 331篇 |
物理学 | 664篇 |
出版年
2024年 | 3篇 |
2023年 | 47篇 |
2022年 | 65篇 |
2021年 | 81篇 |
2020年 | 102篇 |
2019年 | 71篇 |
2018年 | 61篇 |
2017年 | 66篇 |
2016年 | 95篇 |
2015年 | 87篇 |
2014年 | 92篇 |
2013年 | 139篇 |
2012年 | 158篇 |
2011年 | 172篇 |
2010年 | 92篇 |
2009年 | 113篇 |
2008年 | 125篇 |
2007年 | 119篇 |
2006年 | 92篇 |
2005年 | 94篇 |
2004年 | 54篇 |
2003年 | 42篇 |
2002年 | 40篇 |
2001年 | 45篇 |
2000年 | 46篇 |
1999年 | 37篇 |
1998年 | 26篇 |
1997年 | 28篇 |
1996年 | 42篇 |
1995年 | 35篇 |
1994年 | 34篇 |
1993年 | 29篇 |
1992年 | 24篇 |
1991年 | 33篇 |
1990年 | 25篇 |
1989年 | 14篇 |
1988年 | 15篇 |
1987年 | 13篇 |
1986年 | 11篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1968年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有2521条查询结果,搜索用时 31 毫秒
271.
272.
Guicun Li Shuping Pang Jianhua Liu Zhaobo Wang Zhikun Zhang 《Journal of nanoparticle research》2006,8(6):1039-1044
Polyaniline submicrometer-sized tubes with controllable morphology have been synthesized by chemical oxidative polymerization of aniline with the aid of sodium dodecylbenzenesulfonate. The products were characterized by field-emission scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy, respectively. The effects of the concentrations of sodium dodecylbenzenesulfonate, reaction temperatures and growth conditions on the morphologies of polyaniline submicrometer-sized tubes have been investigated. 相似文献
273.
A planar lightwave circuit (PLC) add-drop filter is proposed and analyzed, which consists of a symmetric Mach-Zehnder interferometer (MZI) combined with double microring resonators. A critical coupling condition is derived for a better box-like drop spectrum. Comparisons of its characteristics with other schemes,such as a MZI with a single ring resonator, are presented, and some of the issues about device design and fabrication are also discussed. 相似文献
274.
The aggregation and rearrangement of nanoparticles embedded in a thin cell of ferrofluid at various applied magnetic fields was studied by Monte Carlo simulation. Regular microcolumns with the axis parallel to the magnetic field were observed with column size and spacing depending on the ramp speed of the applied field. Our model successfully simulated the reported experimental results that the column size decreases as the ramp speed increases, which is attributed to the diminishing time to achieve the final assembled state at a given final magnetic field. Column arrays of tunable lattice constants characterizing various spectroscopic dispersions are elucidated. The hexagonal structure of the aggregation of magnetic nanoparticles and optical dispersion were observed through an optical microscope. The transmission diffraction spectra depending on column spacings and sizes of the column array are simulated to yield results comparable to the experiment. 相似文献
275.
Xiao-feng Pang 《International Journal of Infrared and Millimeter Waves》2002,23(3):375-391
thermally biological effects of infrared lights absorbed have been studied by nonlinear quantum theory and molecular biological theory on the basis of structures of cell and water molecules. There is a large number of water in the living systems, it play an important role in living activity, and has a lot of biological functions. There would be no life without water. We can confirm that the thermally biological effect is a result produced by disorder motions of bio-water-molecules according to the essence of heat, feature of molecular structure of water, theory of molecular physics, principle of resonante absorption and experimental fact that infrared light can heat liquid water. Therefore, mechanism of this effect is that the infrared light absorbed results in the quantum vibrations of water molecules with hydrogen bonds, the vibrational energy again transformes as thermal energy of disorder motions of a great number of water molecules in the living systems. The heating waters can cause a lot of biological effects and phenomena to occur in the living systems. Therefore, the infrared lights absorbed by the living systems have some medical functions. 相似文献
276.
This paper presents a globally convergent and locally superlinearly convergent method for solving a convex minimization problem whose objective function has a semismooth but nondifferentiable gradient. Applications to nonlinear minimax problems, stochastic programs with recourse, and their extensions are discussed.The research of the first author is based on work supported by the National Science Foundation under Grants DDM-9104078 and CCR-9213739. This research was carried out while he was visiting the University of New South Wales. The research of the second author is based on work supported by the Australian Research Council. 相似文献
277.
278.
Atomically resolved non-contact fm mode atomic force microscopy images have been obtained from TiO2(100) surfaces. The 1×1 surface is observed, as well as the 1×3 phase previously imaged with STM. The morphology of the latter reconstruction consists of (110) microfacets. An additional reconstruction with 1×3 symmetry is observed, which is assigned to a phase intermediate between the 1×1 and 1×3-microfacet terminations. 相似文献
279.
280.
Asymmetric variational inequality problems over product sets: Applications and iterative methods 总被引:5,自引:0,他引:5
Jong-Shi Pang 《Mathematical Programming》1985,31(2):206-219
In this paper, we (i) describe how several equilibrium problems can be uniformly modelled by a finite-dimensional asymmetric
variational inequality defined over a Cartesian product of sets, and (ii) investigate the local and global convergence of
various iterative methods for solving such a variational inequality problem. Because of the special Cartesian product structure,
these iterative methods decompose the original variational inequality problem into a sequence of simpler variational inequality
subproblems in lower dimensions. The resulting decomposition schemes often have a natural interpretation as some adjustment
processes.
This research was based on work supported by the National Science Foundation under grant ECS 811–4571. 相似文献