全文获取类型
收费全文 | 23745篇 |
免费 | 3517篇 |
国内免费 | 1964篇 |
专业分类
化学 | 4854篇 |
晶体学 | 273篇 |
力学 | 4311篇 |
综合类 | 348篇 |
数学 | 11095篇 |
物理学 | 8345篇 |
出版年
2024年 | 52篇 |
2023年 | 228篇 |
2022年 | 326篇 |
2021年 | 423篇 |
2020年 | 633篇 |
2019年 | 550篇 |
2018年 | 551篇 |
2017年 | 665篇 |
2016年 | 705篇 |
2015年 | 564篇 |
2014年 | 1094篇 |
2013年 | 1603篇 |
2012年 | 1299篇 |
2011年 | 1541篇 |
2010年 | 1384篇 |
2009年 | 1481篇 |
2008年 | 1614篇 |
2007年 | 1696篇 |
2006年 | 1466篇 |
2005年 | 1362篇 |
2004年 | 1252篇 |
2003年 | 1252篇 |
2002年 | 1024篇 |
2001年 | 868篇 |
2000年 | 777篇 |
1999年 | 678篇 |
1998年 | 627篇 |
1997年 | 513篇 |
1996年 | 426篇 |
1995年 | 403篇 |
1994年 | 317篇 |
1993年 | 271篇 |
1992年 | 247篇 |
1991年 | 220篇 |
1990年 | 165篇 |
1989年 | 141篇 |
1988年 | 128篇 |
1987年 | 100篇 |
1986年 | 83篇 |
1985年 | 88篇 |
1984年 | 73篇 |
1983年 | 35篇 |
1982年 | 79篇 |
1981年 | 58篇 |
1980年 | 39篇 |
1979年 | 34篇 |
1978年 | 21篇 |
1977年 | 13篇 |
1976年 | 13篇 |
1973年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 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.
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
3.
4.
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
5.
6.
7.
Tsuguo SUNAMURA 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2015,91(9):481-500
Substantial progress in research on the recession of coastal cliffs composed of soft materials has been made in recent years and data with higher accuracy have been accumulated. This paper provides the state of the art review in the recession studies and highlights two new findings obtained from the reanalysis of existing data. The review topics are: episodic and localized nature of cliff recession; the development of cliffline; the relationship between cliff height and recession rate; mechanisms of cliff toe erosion by waves; a fundamental equation for wave-induced toe erosion; factors controlling toe erosion; and slope instabilities and mass movements. The findings are presented on (1) the temporal change in cliffline recession mode and (2) the effect of beach sediment at the cliff base on the cliff erosion. 相似文献
8.
9.
Bobby Wilson 《偏微分方程通讯》2015,40(8):1521-1542
This article explores the questions of long time orbital stability in high order Sobolev norms of plane wave solutions to the NLSE in the defocusing case. 相似文献
10.
The zero dissipation limit of the one-dimensional non-isentropic micropolar equations is studied in this paper. If the given rarefaction wave which connects to vacuum at one side, a sequence of solution to the micropolar equations can be constructed which converge to the above rarefaction wave with vacuum as the viscosity and the heat conduction coefficient tend to zero. Moreover, the uniform convergence rate is obtained. The key point in our analysis is how to control the degeneracies in the vacuum region in the zero dissipation limit process. 相似文献