全文获取类型
收费全文 | 3596篇 |
免费 | 104篇 |
国内免费 | 22篇 |
专业分类
化学 | 2494篇 |
晶体学 | 31篇 |
力学 | 73篇 |
数学 | 588篇 |
物理学 | 536篇 |
出版年
2022年 | 18篇 |
2021年 | 25篇 |
2020年 | 40篇 |
2019年 | 52篇 |
2018年 | 40篇 |
2017年 | 30篇 |
2016年 | 68篇 |
2015年 | 61篇 |
2014年 | 97篇 |
2013年 | 191篇 |
2012年 | 153篇 |
2011年 | 179篇 |
2010年 | 123篇 |
2009年 | 115篇 |
2008年 | 166篇 |
2007年 | 156篇 |
2006年 | 152篇 |
2005年 | 146篇 |
2004年 | 119篇 |
2003年 | 108篇 |
2002年 | 111篇 |
2001年 | 62篇 |
2000年 | 72篇 |
1999年 | 45篇 |
1998年 | 59篇 |
1997年 | 51篇 |
1996年 | 61篇 |
1995年 | 58篇 |
1994年 | 49篇 |
1993年 | 54篇 |
1992年 | 52篇 |
1991年 | 64篇 |
1990年 | 39篇 |
1989年 | 49篇 |
1988年 | 56篇 |
1987年 | 44篇 |
1986年 | 57篇 |
1985年 | 55篇 |
1984年 | 61篇 |
1983年 | 41篇 |
1982年 | 35篇 |
1981年 | 45篇 |
1980年 | 55篇 |
1979年 | 40篇 |
1978年 | 39篇 |
1977年 | 36篇 |
1976年 | 31篇 |
1975年 | 27篇 |
1974年 | 23篇 |
1973年 | 22篇 |
排序方式: 共有3722条查询结果,搜索用时 15 毫秒
121.
122.
Dr. James Biggs Dr. Karsten Danielmeier Dr. Julia Hitzbleck Dr. Jens Krause Tom Kridl Dr. Stephan Nowak Dr. Enrico Orselli Dr. Xina Quan Dirk Schapeler Will Sutherland Dr. Joachim Wagner 《Angewandte Chemie (International ed. in English)》2013,52(36):9409-9421
We present the development and applications of dielectric elastomers. For the last 10 years the significance of this class of polymers has risen as more applications seem possible and first products have been commercialized. 相似文献
123.
Growth of heterogeneously nucleated, wall based crystals plays a major role in determining the micro-structure during melt casting. This issue is here addressed using a model system of charged colloidal spheres in deionized aqueous suspension observed by Bragg microscopy which is a combination of light scattering and microscopy. We examine the evolution of the three-dimensional size, shape, and orientation of twin domains in monolithic crystals growing from two opposing planar walls into a meta-stable (shear-) melt. At each wall crystal orientation and twinning emerges during nucleation with small domains. During growth these widen and merge. From image analysis we observe the lateral coarsening velocities to follow a power law behaviour L(XY) ∝ t(1∕2) as long as the vertical growth continues at constant speed. Lateral coarsening terminates upon intersection of the two solids and hardly any further ripening is seen. Initial lateral coarsening velocities show a Wilson Frenkel type dependence on the melt meta-stability. 相似文献
124.
125.
126.
127.
128.
Potential Analysis - In the present paper, we are going to show that outside a slim set in the sense of Malliavin (or quasi-surely), the signature path (which consists of iterated path integrals in... 相似文献
129.
Dr. Maria Książek Dr. Marek Weselski Marcin Kaźmierczak Aleksandra Tołoczko Dr. Miłosz Siczek Dr. Piotr Durlak Dr. Juliusz A. Wolny Prof. Dr. Volker Schünemann Prof. Dr. Joachim Kusz Dr. Robert Bronisz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(63):14419-14434
Reaction of 1,2-di(tetrazol-2-yl)ethane (ebtz) with Fe(BF4)2⋅6 H2O in different nitriles yields one-dimensional coordination polymers [Fe(ebtz)2(RCN)2](BF4)2⋅nRCN (n=2 for R=CH3 ( 1 ) and n=0 for R=C2H5 ( 2 ) C3H7 ( 3 ), C3H5 ( 4 ), CH2Cl ( 5 )) exhibiting spin crossover (SCO). SCO in 1 and 3 – 5 is complete and occurs above 160 K. In 2 , it is shifted to lower temperatures and is accompanied by wide hysteresis (T1/2↓=78 K, T1/2↑=123 K) and proceeds extremely slowly. Isothermal (80 K) time-resolved single-crystal X-ray diffraction studies revealed a complex nature for the HS→LS transition in 2 . An initial, slow stage is associated with shrinkage of polymeric chains and with reduction of volume at 77 % (in relation to the difference between cell volumes VHS−VLS) whereas only 16 % of iron(II) ions change spin state. In the second stage, an abrupt SCO occurs, associated with breathing of the crystal lattice along the direction of the Fe–nitrile bonds, while the nitriles reorient. HS→LS switching triggered by light (808 nm) reveals the coupling of spin state and nitrile orientation. The importance of this coupling was confirmed by studies of [Fe(ebtz)2(C2H5CN/C3H7CN)2](BF4)2 mixed crystals ( 2 a , 2 b ), showing a shift of T1/2 to higher values and narrowing of the hysteresis loop concomitant with an increase of the fraction of butyronitrile. This increase reduces the capability of nitrile molecules to reorient. Density functional theory (DFT) studies of models of 1 – 5 suggest a particular possibility of 2 to adopt a low (140–145°) value of its Fe-N-C(propionitrile) angle. 相似文献
130.