全文获取类型
收费全文 | 11426篇 |
免费 | 1514篇 |
国内免费 | 956篇 |
专业分类
化学 | 3026篇 |
晶体学 | 69篇 |
力学 | 808篇 |
综合类 | 242篇 |
数学 | 4598篇 |
物理学 | 5153篇 |
出版年
2023年 | 83篇 |
2022年 | 275篇 |
2021年 | 302篇 |
2020年 | 253篇 |
2019年 | 230篇 |
2018年 | 247篇 |
2017年 | 333篇 |
2016年 | 363篇 |
2015年 | 313篇 |
2014年 | 590篇 |
2013年 | 805篇 |
2012年 | 595篇 |
2011年 | 692篇 |
2010年 | 582篇 |
2009年 | 692篇 |
2008年 | 787篇 |
2007年 | 764篇 |
2006年 | 670篇 |
2005年 | 630篇 |
2004年 | 511篇 |
2003年 | 490篇 |
2002年 | 474篇 |
2001年 | 336篇 |
2000年 | 345篇 |
1999年 | 328篇 |
1998年 | 319篇 |
1997年 | 246篇 |
1996年 | 205篇 |
1995年 | 181篇 |
1994年 | 187篇 |
1993年 | 119篇 |
1992年 | 116篇 |
1991年 | 90篇 |
1990年 | 71篇 |
1989年 | 81篇 |
1988年 | 73篇 |
1987年 | 65篇 |
1986年 | 47篇 |
1985年 | 73篇 |
1984年 | 47篇 |
1983年 | 34篇 |
1982年 | 47篇 |
1981年 | 23篇 |
1980年 | 22篇 |
1979年 | 28篇 |
1978年 | 33篇 |
1977年 | 19篇 |
1976年 | 20篇 |
1975年 | 10篇 |
1973年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Keiichiro Shiraga Yuichi Ogawa Shojiro Kikuchi Masayuki Amagai Takeshi Matsui 《Molecules (Basel, Switzerland)》2022,27(9)
While bulk water and hydration water coexist in cells to support the expression of biological macromolecules, how the dynamics of water molecules, which have long been only a minor role in molecular biology research, relate to changes in cellular states such as cell death has hardly been explored so far due to the lack of evaluation techniques. In this study, we developed a high-precision measurement system that can discriminate bulk water content changes of ±0.02% (0.2 mg/cm3) with single-cell-level spatial resolution based on a near-field CMOS dielectric sensor operating at 65 GHz. We applied this system to evaluate the temporal changes in the bulk water content during the cell death process of keratinocytes, called corneoptosis, using isolated SG1 (first layer of stratum granulosum) cells in vitro. A significant irreversible increase in the bulk water content was observed approximately 1 h before membrane disruption during corneoptosis, which starts with cytoplasmic high Ca2+ signal. These findings suggest that the calcium flux may have a role in triggering the increase in the bulk water content in SG1 cells. Thus, our near-field CMOS dielectric sensor provides a valuable tool to dissect the involvement of water molecules in the various events that occur in the cell. 相似文献
32.
A new Markov process describing crystal growth in three dimensions is introduced. States of the process are configurations of the crystal surface, which has a terrace-edge-kink structure. The states are continuous along edges but discrete across edges, in accordance with the very different rates for the two types of captures of particles. Stationary distributions, describing steady crystal growth, are found in general. To our knowledge, these are the first examples of stationary distributions for layered crystal growth in three dimensions. The steady growth rate and other quantities are obtained explicitly for two interacting edges. For many interacting edges, growth behavior is determined (a) in various asymptotic regimes including thermodynamic limits, (b) via simulations, and (c) using series (cluster) expansions in the slope of the surface, the first three coefficients being computed. The theoretical growth rates show a marked dependence on surface dimensions. This may contribute to the size dependence and dispersion in the observed growth rate of small crystals. 相似文献
33.
34.
改进了文献中报导的Boltzmann基本方程。与Boltzmann基本方程相比,改进后的Boltzmann方程更全面地描述了电子与基态氩原子碰撞的物理过程,并能计算出整个能量区间的电子分布。利用Boltzmann基本方程和改进的Boltzmann方程,对电子束泵浦氩中能量大于氩原子第一激发态能量(11.56eV)的高能电子分布函数进行了理论计算。计算中,选取了电子碰撞氩的微分电离截面和激发截面的解析表达式。对计算所得的稳态电子分布函数以及达到稳态分布所需的特征时间进行了分析和讨论。 相似文献
35.
36.
Analysis of electron energy distribution function in a magnetically filtered complex plasma 下载免费PDF全文
The electron energy distribution function (EEDF) for a magnetically filtered dusty plasma is studied in a dusty double plasma device where the electron energy can be varied from 0.15 eV to ~ 2.8 eV and plasma density from 10 6 cm-3 to 10 9cm-3 . The characteristics of EEDF for these ranges of plasma parameters are investigated in a pristine plasma as well as in a dusty plasma. The results show that in the presence of dust, there is a drastic modification in EEDF patterns in a plasma with higher electron temperature and density than those in a low temperature and low density plasma produced by the magnetic filter. 相似文献
37.
《Physics and Chemistry of Liquids》2012,50(6):819-821
The recent study of He and You [P.-S. He and W.-L. You, Int. J. Mod. Phys. B26, 1250107 (2012)] on the relation between superfluid and condensate densities in a two-dimensional weakly interacting Boson system assumed a δ(x???x′) interaction between two particles at sites x and x′. The main purpose of this article is to point out the sensitivity of the conclusions of He and You to the choice of interaction. Thus, it is known for logarithmic interactions that one can have superfluidity without a condensate. Finally, some related ideas are mentioned in relation to superfluidity in liquid 4 He at exceedingly low temperatures. 相似文献
38.
39.
Shigeru Shinomoto 《Journal of statistical physics》1983,32(1):105-113
It is found that the density expansion in the argument of the exponential function gives a fine convergence on the equation of state of the hard-sphere system. The pair distribution function and the equation of state is constructed by an intuitive kinetic theoretical method. The equation of state of the hard-core system with attractive potential is constructed semiempirically with the aid of this simple analytical result, and Kamerling-Onnes' constant of the critical point is obtained analytically. 相似文献
40.
H. Dette
N. Henze
《Statistics & probability letters》1990,10(5):381-390Let Dn,r denote the largest rth nearest neighbor link for n points drawn independently and uniformly from the unit d-cube Cd. We show that according as r < d or r>d, the limiting behavior of Dn,r, as n → ∞, is determined by the two-dimensional ‘faces’ respectively one-dimensional ‘edges’ of the boundary of Cd. If d = r, a ‘balance’ between faces and edges occurs. In case of a d-dimensional sphere (instead of a cube) the boundary dominates the asymptotic behavior of Dn,r if d 3 or if d = 2, r 3. 相似文献