全文获取类型
收费全文 | 482篇 |
免费 | 40篇 |
专业分类
化学 | 433篇 |
晶体学 | 2篇 |
力学 | 6篇 |
数学 | 33篇 |
物理学 | 48篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 13篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2016年 | 17篇 |
2015年 | 24篇 |
2014年 | 19篇 |
2013年 | 30篇 |
2012年 | 44篇 |
2011年 | 33篇 |
2010年 | 33篇 |
2009年 | 28篇 |
2008年 | 25篇 |
2007年 | 30篇 |
2006年 | 28篇 |
2005年 | 24篇 |
2004年 | 21篇 |
2003年 | 22篇 |
2002年 | 19篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1956年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有522条查询结果,搜索用时 15 毫秒
101.
102.
Laura Ramn‐Gimenez Rebekka Storz Johannes Haberl Heino Finkelmann Anke Hoffmann 《Macromolecular rapid communications》2012,33(5):386-391
New mesogens presenting smectic A (SmA) phases and capable of hosting lithium salts are designed. The mesogens comprise a vinyl‐functionalized spacer to allow further reaction to the polymer backbone, an aromatic core and ethylene oxide chains, able to coordinate lithium ions. Copolymerizing these monomers with a suitable crosslinker yields the first lithium containing liquid crystalline elastomers (LCEs). The SmA structure where the ethylene oxide chains are microphase separated in layers is fixed by the crosslinking and permanent macroscopic orientation is obtained. Diffusion and conductivity measurements of the monomer sample show a large anisotropy of the ion mobility (100 for the cation and 400 for the anion). In the elastomer the anisotropy of the lithium mobility is comparable to that in the monomers. 相似文献
103.
Passivity analysis of stochastic neural networks with time-varying delays and parametric uncertainties is investigated in this paper. Passivity of stochastic neural networks is defined. Both delay-independent and delay-dependent stochastic passivity conditions are presented in terms of linear matrix inequalities (LMIs). The results are established by using the Lyapunov–Krasovskii functional method. In order to derive the delay-dependent passivity criterion, some free-weighting matrices are introduced. The effectiveness of the method is illustrated by numerical examples. 相似文献
104.
Chian Wen Chan Anke Brems Shiva Mahmoudi Jan Baeyens Jonathan Seville David Parker Thomas Leadbeater Joseph Gargiuli 《Particuology》2010,8(6):623-630
Laboratory and industrial risers are equipped with exits of many different layouts, and numerous publications discuss the influence of riser exit geometry on local and overall solids hydrodynamics in the riser. The present paper reviews literature findings--mostly based upon indirect experimental techniques and often somewhat contradictory, Direct measurement of particle velocity and particle occupancy near and in the riser exit provide a better indication of the effect of riser exit geometry. Positron Emission Particle Tracking (PEPT) was used in this work for the first time to investigate the exit region of the riser, An abrupt or sharp exit causes particles to be knocked out of the gas flow, so forming a recirculation or reflux region in the upper part of the riser. This is much less pronounced with a curved or gradual exit. 相似文献
105.
106.
107.
Jing Hu Qimin Zhang Anke Meyer-Baese Ming Ye 《Mathematical Methods in the Applied Sciences》2020,43(17):9706-9718
In this paper, based on the pathogenesis of Alzheimer's disease, we investigate a stochastic mathematical model, focusing on the dynamics of β-amyloid (Aβ) plaques, Aβ oligomers, PrPC proteins, and the Aβ-x-PrPC complex. Within the framework of the Lyapunov method, we first show existence and uniqueness of global positive solution of the model and then establish the sufficient conditions for existence of an ergodic stationary distribution of the positive solution. Ultimately, numerical examples are presented to illustrate the effectiveness of theoretical results. 相似文献
108.
109.
110.