全文获取类型
收费全文 | 587篇 |
免费 | 19篇 |
国内免费 | 2篇 |
专业分类
化学 | 402篇 |
晶体学 | 3篇 |
力学 | 9篇 |
数学 | 86篇 |
物理学 | 108篇 |
出版年
2023年 | 7篇 |
2022年 | 14篇 |
2021年 | 24篇 |
2020年 | 30篇 |
2019年 | 30篇 |
2018年 | 19篇 |
2017年 | 11篇 |
2016年 | 13篇 |
2015年 | 14篇 |
2014年 | 22篇 |
2013年 | 37篇 |
2012年 | 43篇 |
2011年 | 55篇 |
2010年 | 31篇 |
2009年 | 12篇 |
2008年 | 23篇 |
2007年 | 23篇 |
2006年 | 35篇 |
2005年 | 45篇 |
2004年 | 20篇 |
2003年 | 16篇 |
2002年 | 19篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 8篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1994年 | 4篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1955年 | 1篇 |
1935年 | 1篇 |
排序方式: 共有608条查询结果,搜索用时 109 毫秒
511.
512.
Vladislav N. Kovalnogov Theodore E. Simos Charalampos Tsitouras 《Mathematical Methods in the Applied Sciences》2020,43(7):4918-4926
In the present paper, the second-order linear inhomogeneous initial value problems (LI-IVP) with constant coefficients is of our interest. Two-step hybrid methods (ie, of Numerov-type) are considered for addressing this problem. Thus, a special set of order conditions is given and solved for derivation a low cost new method. Actually, we manage to save two stages per step. This is crucial as shown in various numerical tests where our new proposal outperforms standard methods in the relevant literature. 相似文献
513.
Vladislav Kargin 《Journal of statistical physics》2014,157(1):70-83
The paper provides a new integral formula for the largest Lyapunov exponent of Gaussian matrices, which is valid in the real, complex and quaternion-valued cases. This formula is applied to derive asymptotic expressions for the largest Lyapunov exponent when the size of the matrix is large and compare the Lyapunov exponents in models with a spike and no spikes. 相似文献
514.
Vladislav A. Tuskaev Svetlana Ch. Gagieva Dmitry A. Kurmaev Elizaveta K. Melnikova Sergey V. Zubkevich Mikhail I. Buzin Galina G. Nikiforova Viktor G. Vasil'ev Daniele Saracheno Vyacheslav S. Bogdanov Viktor I. Privalov Boris M. Bulychev 《应用有机金属化学》2020,34(11):e5933
Titanium(IV) coordination compounds are effectively used as precatalysts for ethylene polymerization and copolymerization with other olefins. New titanium(IV) complexes 3b – d with ligands containing two diphenylcarbinol fragments linked by the perfluorinated hydrocarbon units –CF2– or –C2F4– were synthesized. The structures of complexes 3b and 3d were determined by X-ray diffraction. Titanium atoms in 3b have a distorted trigonal-bipyramidal coordination environment while spiro-complex 3d is characterized by tetrahedral molecular geometry. The catalytic behavior of complexes activated by mixtures of Bu2Mg and alkylaluminium chlorides from among Me2AlCl, Et2AlCl, EtAlCl2, and Et3Al2Cl3 were studied. The resulting catalytic systems catalyze ethylene polymerization to afford ultra-high molecular weight polyethylene, suitable for modern processing methods, and the solvent-free solid state formation of super high-strength (1.37–2.75 GPa) and high-modulus (up to 138 GPa) oriented film tapes. The same catalytic systems catalyze ethylene copolymerization with 1-hexene to afford high molecular weight semicrystalline elastomeric polymers containing up to 20% of comonomer units. 相似文献
515.
Back Cover: Giant Volume Change and Topological Gaps in Temperature‐ and Pressure‐Induced Phase Transitions: Experimental and Computational Study of ThMo2O8 (Chem. Eur. J. 3/2016)
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
516.
517.
The adsorption of a water molecule on a basal Bi(111) electrode surface, crystallising in the rhombohedral system, has been studied in the framework of cluster model. The quantum chemical calculations were performed at the Density Functional Theory (DFT) level and the electrical double layer effects were analysed by using an external electric field. In contrast to computational predictions reported previously for other metal surfaces, crystallising in the face-centred cubic or hexagonal close-packed systems, a hollow site for Bi(111) was found to be energetically the most preferable; the water adsorption energy amounts to ? 28 kJ mol? 1. In a wide range of surface charge densities the water molecule is bound preferentially through the O atom in orientation perpendicular to the surface plane. The Bi(111) hydrophilic properties are compared with those for other metals. Some adsorption characteristics of a hydrogen atom and a hydroxyl group at Bi(111) are reported as well, which give evidence in favour of the non-dissociative adsorption of water molecules. 相似文献
518.
Alexey Y. Barkov Nikolay S. Zimnitskiy Igor B. Kutyashev Vladislav Y. Korotaev Vyacheslav Y. Sosnovskikh 《Tetrahedron letters》2017,58(42):3989-3992
The reactions of 3-nitro-2-phenyl-2H-chromenes with 2-arylmethylidene-5-oxopyrazolidin-2-ium-1-ides proceeded diastereoselectively to afford the corresponding tetrahydrochromeno[4,3-c]pyrazolo[1,2-a]pyrazol-11-ones in good yields as a result of the 1,3-dipolar cycloaddition reaction of stabilised N,N′-cyclic azomethine imines at the Δ3-bond of the chromene system. 相似文献
519.