全文获取类型
收费全文 | 19006篇 |
免费 | 1864篇 |
国内免费 | 1691篇 |
专业分类
化学 | 3795篇 |
晶体学 | 239篇 |
力学 | 2517篇 |
综合类 | 277篇 |
数学 | 12475篇 |
物理学 | 3258篇 |
出版年
2024年 | 40篇 |
2023年 | 182篇 |
2022年 | 219篇 |
2021年 | 303篇 |
2020年 | 465篇 |
2019年 | 450篇 |
2018年 | 427篇 |
2017年 | 516篇 |
2016年 | 533篇 |
2015年 | 411篇 |
2014年 | 792篇 |
2013年 | 1455篇 |
2012年 | 903篇 |
2011年 | 1103篇 |
2010年 | 1075篇 |
2009年 | 1208篇 |
2008年 | 1348篇 |
2007年 | 1361篇 |
2006年 | 1133篇 |
2005年 | 1021篇 |
2004年 | 917篇 |
2003年 | 982篇 |
2002年 | 800篇 |
2001年 | 656篇 |
2000年 | 596篇 |
1999年 | 536篇 |
1998年 | 502篇 |
1997年 | 406篇 |
1996年 | 331篇 |
1995年 | 282篇 |
1994年 | 260篇 |
1993年 | 183篇 |
1992年 | 160篇 |
1991年 | 127篇 |
1990年 | 110篇 |
1989年 | 76篇 |
1988年 | 86篇 |
1987年 | 67篇 |
1986年 | 67篇 |
1985年 | 76篇 |
1984年 | 63篇 |
1983年 | 36篇 |
1982年 | 72篇 |
1981年 | 54篇 |
1980年 | 37篇 |
1979年 | 37篇 |
1978年 | 23篇 |
1977年 | 14篇 |
1976年 | 20篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 609 毫秒
1.
Shilin Jiang Dr. Yalan Liu Dr. Lin Wang Prof. Zhifang Chai Prof. Wei-Qun Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(60):e202201145
The coordination chemistry of f-block elements (lanthanide and actinide) in molten salts has become a resounding topic in view of its great importance to the research and development (R&D) of molten salt reactors and pyroprocessing. In this Review article, a general overview of the coordination chemistry of f-block elements in molten salts is provided including past achievements and recent advances. Particular emphases are placed on the oxidation state, speciation, and solution structure of f-block metal ions in molten salts, as well as their relationships with the salt composition. Furthermore, this review briefly discusses the spectroscopic and theoretical methods that complement each other in revealing the coordination properties. 相似文献
2.
3.
Prof. Dr. Peter Hess 《Chemphyschem》2022,23(6):e202100880
In the periodic table the position of each atom follows the ‘aufbau’ principle of the individual electron shells. The resulting intrinsic periodicity of atomic properties determines the overall behavior of atoms in two-dimensional (2D) bonding and structure formation. Insight into the type and strength of bonding is the key in the discovery of innovative 2D materials. The primary features of 2D bonding and the ensuing monolayer structures of the main-group II–VI elements result from the number of valence electrons and the change of atom size, which determine the type of hybridization. The results reveal the tight connection between strength of bonding and bond length in 2D networks. The predictive power of the periodic table reveals general rules of bonding, the bonding-structure relationship, and allows an assessment of published data of 2D materials. 相似文献
4.
5.
Tomoyuki Nakatsuka 《Mathematische Nachrichten》2021,294(1):98-117
We study the existence of a time‐periodic solution with pointwise decay properties to the Navier–Stokes equation in the whole space. We show that if the time‐periodic external force is sufficiently small in an appropriate sense, then there exists a time‐periodic solution of the Navier–Stokes equation such that and uniformly in as . Our solution decays faster than the time‐periodic Stokes fundamental solution and the faster decay of its spatial derivatives of higher order is also described. 相似文献
6.
In this article, we construct and analyze a residual-based a posteriori error estimator for a quadratic finite volume method (FVM) for solving nonlinear elliptic partial differential equations with homogeneous Dirichlet boundary conditions. We shall prove that the a posteriori error estimator yields the global upper and local lower bounds for the norm error of the FVM. So that the a posteriori error estimator is equivalent to the true error in a certain sense. Numerical experiments are performed to illustrate the theoretical results. 相似文献
7.
Laurens Kooijman Dr. Matthias Schuster Christian Baumann Simon Jurt Dr. Frank Löhr Dr. Boris Fürtig Prof. Dr. Peter Güntert Prof. Dr. Oliver Zerbe 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21151-21158
To achieve efficient proton pumping in the light-driven proton pump bacteriorhodopsin (bR), the protein must be tightly coupled to the retinal to rapidly convert retinal isomerization into protein structural rearrangements. Methyl group dynamics of bR embedded in lipid nanodiscs were determined in the dark-adapted state, and were found to be mostly well ordered at the cytosolic side. Methyl groups in the M145A mutant of bR, which displays only 10 % residual proton pumping activity, are less well ordered, suggesting a link between side-chain dynamics on the cytosolic side of the bR cavity and proton pumping activity. In addition, slow conformational exchange, attributed to low frequency motions of aromatic rings, was indirectly observed for residues on the extracellular side of the bR cavity. This may be related to reorganization of the water network. These observations provide a detailed picture of previously undescribed equilibrium dynamics on different time scales for ground-state bR. 相似文献
8.
Florence Drui Emmanuel Franck Philippe Helluy Laurent Navoret 《Comptes Rendus Mecanique》2019,347(3):259-269
The over-relaxation approach is an alternative to the Jin–Xin relaxation method in order to apply the equilibrium source term in a more precise way. This is also a key ingredient of the lattice Boltzmann method for achieving second-order accuracy. In this work, we provide an analysis of the over-relaxation kinetic scheme. We compute its equivalent equation, which is particularly useful for devising stable boundary conditions for the hidden kinetic variables. 相似文献
9.
10.