全文获取类型
收费全文 | 12217篇 |
免费 | 646篇 |
国内免费 | 57篇 |
专业分类
化学 | 8845篇 |
晶体学 | 39篇 |
力学 | 297篇 |
数学 | 1987篇 |
物理学 | 1752篇 |
出版年
2023年 | 91篇 |
2022年 | 117篇 |
2021年 | 205篇 |
2020年 | 293篇 |
2019年 | 306篇 |
2018年 | 150篇 |
2017年 | 168篇 |
2016年 | 453篇 |
2015年 | 480篇 |
2014年 | 492篇 |
2013年 | 672篇 |
2012年 | 931篇 |
2011年 | 935篇 |
2010年 | 579篇 |
2009年 | 500篇 |
2008年 | 746篇 |
2007年 | 714篇 |
2006年 | 652篇 |
2005年 | 647篇 |
2004年 | 507篇 |
2003年 | 415篇 |
2002年 | 395篇 |
2001年 | 192篇 |
2000年 | 156篇 |
1999年 | 151篇 |
1998年 | 158篇 |
1997年 | 156篇 |
1996年 | 130篇 |
1995年 | 97篇 |
1994年 | 92篇 |
1993年 | 105篇 |
1992年 | 74篇 |
1991年 | 74篇 |
1990年 | 59篇 |
1989年 | 78篇 |
1988年 | 63篇 |
1987年 | 42篇 |
1986年 | 51篇 |
1985年 | 64篇 |
1984年 | 55篇 |
1983年 | 55篇 |
1982年 | 55篇 |
1981年 | 66篇 |
1980年 | 49篇 |
1979年 | 50篇 |
1978年 | 49篇 |
1977年 | 49篇 |
1976年 | 53篇 |
1975年 | 46篇 |
1973年 | 36篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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
2.
3.
4.
5.
6.
7.
8.
In 1976 S. Hawking claimed that “Because part of the information about the state of the system is lost down the hole, the final situation is represented by a density matrix rather than a pure quantum state”. 1 This was the starting point of the popular “black hole (BH) information paradox”. 相似文献
9.
P. W. J. Glover 《Transport in Porous Media》2018,124(1):31-56
In this paper, we have significantly modified an existing model for calculating the zeta potential and streaming potential coefficient of porous media and tested it with a large, recently published, high-quality experimental dataset. The newly modified model does not require the imposition of a zeta potential offset but derives its high salinity zeta potential behaviour from Stern plane saturation considerations. The newly modified model has been implemented as a function of temperature, salinity, pH, and rock microstructure both for facies-specific aggregations of the new data and for individual samples. Since the experimental data include measurements on samples of both detrital and authigenic overgrowth sandstones, it was possible to model and test the effect of widely varying microstructural properties while keeping lithology constant. The results show that the theoretical model represents the experimental data very well when applied to model data for a particular lithofacies over the whole salinity, from 10?5 to 6.3 mol/dm3, and extremely well when modelling individual samples and taking individual sample microstructure into account. The new model reproduces and explains the extreme sensitivity of zeta and streaming potential coefficient to pore fluid pH. The low salinity control of streaming potential coefficient by rock microstructure is described well by the modified model. The model also behaves at high salinities, showing that the constant zeta potential observed at high salinities arises from the development of a maximum charge density in the diffuse layer as it is compressed to the thickness of one hydrated metal ion. 相似文献
10.