全文获取类型
收费全文 | 1019篇 |
免费 | 66篇 |
专业分类
化学 | 857篇 |
晶体学 | 11篇 |
力学 | 27篇 |
数学 | 48篇 |
物理学 | 142篇 |
出版年
2023年 | 7篇 |
2022年 | 18篇 |
2021年 | 24篇 |
2020年 | 22篇 |
2019年 | 21篇 |
2018年 | 19篇 |
2017年 | 18篇 |
2016年 | 40篇 |
2015年 | 37篇 |
2014年 | 59篇 |
2013年 | 70篇 |
2012年 | 97篇 |
2011年 | 102篇 |
2010年 | 60篇 |
2009年 | 46篇 |
2008年 | 86篇 |
2007年 | 58篇 |
2006年 | 66篇 |
2005年 | 58篇 |
2004年 | 48篇 |
2003年 | 38篇 |
2002年 | 28篇 |
2001年 | 20篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有1085条查询结果,搜索用时 15 毫秒
71.
Dr. Muhammad Ehsan Dr. Yang Du Jonas S. Mortensen Dr. Parameswaran Hariharan Qianhui Qu Lubna Ghani Dr. Manabendra Das Anne Grethen Prof. Bernadette Byrne Prof. Georgios Skiniotis Prof. Sandro Keller Prof. Claus J. Loland Prof. Lan Guan Prof. Brian K. Kobilka Prof. Pil Seok Chae 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(49):11545-11554
Amphipathic agents are widely used in various fields including biomedical sciences. Micelle-forming detergents are particularly useful for in vitro membrane-protein characterization. As many conventional detergents are limited in their ability to stabilize membrane proteins, it is necessary to develop novel detergents to facilitate membrane-protein research. In the current study, we developed novel trimaltoside detergents with an alkyl pendant-bearing terphenyl unit as a hydrophobic group, designated terphenyl-cored maltosides (TPMs). We found that the geometry of the detergent hydrophobic group substantially impacts detergent self-assembly behavior, as well as detergent efficacy for membrane-protein stabilization. TPM-Vs, with a bent terphenyl group, were superior to the linear counterparts (TPM-Ls) at stabilizing multiple membrane proteins. The favorable protein stabilization efficacy of these bent TPMs is likely associated with a binding mode with membrane proteins distinct from conventional detergents and facial amphiphiles. When compared to n-dodecyl-β-d -maltoside (DDM), most TPMs were superior or comparable to this gold standard detergent at stabilizing membrane proteins. Notably, TPM-L3 was particularly effective at stabilizing the human β2 adrenergic receptor (β2AR), a G-protein coupled receptor, and its complex with Gs protein. Thus, the current study not only provides novel detergent tools that are useful for membrane-protein study, but also suggests a critical role for detergent hydrophobic group geometry in governing detergent efficacy. 相似文献
72.
Takaaki Kakitsuka Shinji Matsuo Seok–Hwan Jeong Toru Segawa Hiroshi Okamoto Yoshihiro Kawaguchi Yasuhiro Kondo Yuzo Yoshikuni Hiroyuki Suzuki 《Optical and Quantum Electronics》2006,38(12-14):1053-1060
We theoretically investigated a digitally tunable laser with a chirped ladder filter and a ring resonator to obtain a wide wavelength tuning range covering the whole C- or L- band. The clear relation between the tuning range and laser structure, especially the ladder filter, is described analytically. The introduction of a chirped structure into a ladder filter is effective in achieving both wide tunability and a stable lasing mode. A numerical simulation based on multimode rate equations shows that a tuning range of over 40 nm and a mode suppression ratio over 40 dB can be achieved by introducing a chirped ladder filter. 相似文献
73.
Lee JS Kim YY Kim JS Kang YJ 《The Journal of the Acoustical Society of America》2008,123(4):2094-2106
Optimal shape design of a two-dimensional poroelastic acoustical foam is formulated as a topology optimization problem. For a poroelastic acoustical system consisting of an air region and a poroelastic foam region, two different physical regions are continuously changed in an iterative design process. To automatically account for the moving interfaces between two regions, we propose a new unified model to analyze the whole poroelastic acoustical foam system with one set of governing equations; Biot's equations are modified with a material property interpolation from a topology optimization method. With the unified analysis model, we carry out two-dimensional optimal shape design of a poroelastic acoustical foam by a gradient-based topology optimization setting. The specific objective is the maximization of the absorption coefficient in low and middle ranges of frequencies with different amounts of a poroelastic material. The performances of the obtained shapes are compared with those of well-known wedge shapes, and the improvement of absorption is physically interpreted. 相似文献
74.
We show that the phase transition from the decelerating universe to the accelerating universe, which is of relevance to the cosmological coincidence problem, is possible in the semiclassically quantized two-dimensional dilaton gravity by taking into account the noncommutative field variables during the finite time. Initially, the quantum-mechanically induced energy from the noncommutativity among the fields makes the early universe decelerate and subsequently the universe is accelerating because the dilaton driven cosmology becomes dominant later. 相似文献
75.
This paper concerns with existence and qualitative properties of ground states to generalized nonlinear Schr(o)dinger equations (gNLS) with abstract symbols.Under some structural assumptions on the symbol,we prove a ground state exists and it satisfies several fundamental properties that the ground state to the standard NLS enjoys.Furthermore,by imposing additional assumptions,we construct,in small mass case,a nontrivial radially symmetric solution to gNLS with H1-subcritical nonlinearity,even if the natural energy space does not control the H1-subcritical nonlinearity. 相似文献
76.
77.
78.
Yoon Yeol Yoon Kil Yong Lee Kyung Seok Ko 《Journal of Radioanalytical and Nuclear Chemistry》2010,284(3):591-595
The contents of H-3 and C-14 in groundwater and surface waters around low and medium-level atomic waste repository site in
Korea were determined. The concentrations of C-14 were in the range 0.186–0.287 Bq/L. The H-3 concentration of the groundwaters
and surface waters were <0.06–5.75 and 1.22–4.74 Bq/L. The average H-3 contents of west, north and south direction were 1.18 ± 0.12,
1.11 ± 0.78 and 2.85 ± 2.66. H-3 and C-14 concentrations in the south direction were relatively higher than west and north
direction samples. The surface waters sampled from catchment were four times higher than average H-3 concentration in precipitation.
The concentrations of H-3 and C-14 within 5 km area samples were much higher than other samples. 相似文献
79.
Ahn TK Yoon ZS Hwang IW Lim JK Rhee H Joo T Sim E Kim SK Aratani N Osuka A Kim D 《The journal of physical chemistry. B》2005,109(22):11223-11230
We have investigated the overall excitation energy relaxation dynamics in linear porphyrin arrays as well as the energy transport phenomena by attaching an energy acceptor to one end of a linear porphyrin array by using steady state and time-resolved spectroscopic measurements. We have revealed that the solvation dynamics as well as the conformational dynamics contributes significantly to the energy relaxation processes of linear porphyrin arrays. Consequently, long porphyrin arrays no longer serve as good energy transmission elements in donor-acceptor linked systems due to conformational heterogeneities which provide the non-radiative deactivation channels as energy quenchers. 相似文献
80.
To read out correct data from shift-multiplexed holographic data storage, we propose a novel method of pixel matching by use of a tiny plane-parallel refraction plate placed in the path of converging readout beams. Tilting the refraction plate produces a shift in the lateral position of the readout beam incident upon the holographic storage disk, leading to compensation for pixel-mismatch errors by an improvement in bit-error rate of 3 orders of magnitude. 相似文献