全文获取类型
收费全文 | 4336篇 |
免费 | 124篇 |
国内免费 | 20篇 |
专业分类
化学 | 2807篇 |
晶体学 | 39篇 |
力学 | 79篇 |
数学 | 843篇 |
物理学 | 712篇 |
出版年
2023年 | 40篇 |
2022年 | 92篇 |
2021年 | 125篇 |
2020年 | 98篇 |
2019年 | 122篇 |
2018年 | 132篇 |
2017年 | 111篇 |
2016年 | 151篇 |
2015年 | 121篇 |
2014年 | 125篇 |
2013年 | 271篇 |
2012年 | 236篇 |
2011年 | 302篇 |
2010年 | 192篇 |
2009年 | 193篇 |
2008年 | 241篇 |
2007年 | 227篇 |
2006年 | 223篇 |
2005年 | 210篇 |
2004年 | 174篇 |
2003年 | 137篇 |
2002年 | 113篇 |
2001年 | 71篇 |
2000年 | 53篇 |
1999年 | 38篇 |
1998年 | 38篇 |
1997年 | 33篇 |
1996年 | 26篇 |
1995年 | 22篇 |
1994年 | 25篇 |
1993年 | 32篇 |
1992年 | 17篇 |
1991年 | 31篇 |
1990年 | 17篇 |
1989年 | 14篇 |
1987年 | 15篇 |
1986年 | 20篇 |
1985年 | 22篇 |
1984年 | 30篇 |
1983年 | 20篇 |
1982年 | 20篇 |
1981年 | 27篇 |
1980年 | 22篇 |
1979年 | 25篇 |
1978年 | 26篇 |
1977年 | 27篇 |
1975年 | 20篇 |
1974年 | 15篇 |
1958年 | 13篇 |
1955年 | 15篇 |
排序方式: 共有4480条查询结果,搜索用时 15 毫秒
171.
Dr. Oleksii Zozulia Dr. Liam R. Marshall Dr. Inhye Kim Eric M. Kohn Prof. Dr. Ivan V. Korendovych 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(17):5388-5392
The self-assembly of short peptides gives rise to versatile nanomaterials capable of promoting efficient catalysis. We have shown that short, seven-residue peptides bind hemin to produce functional catalytic materials which display highly efficient peroxidation activity, reaching a catalytic efficiency of 3×105 m −1 s−1. Self-assembly is essential for catalysis as non-assembling controls show no activity. We have also observed peroxidase activity even in the absence of hemin, suggesting the potential to alter redox properties of substrates upon association with the assemblies. These results demonstrate the practical utility of self-assembled peptides in various catalytic applications and further support the evolutionary link between amyloids and modern-day enzymes. 相似文献
172.
173.
Andrey V. Galukhin Elena A. Andreyko Ildar H. Rizvanov Ivan I. Stoikov 《Mendeleev Communications》2013,23(4):196-198
Pentakis-thiacalix[4]arenes containing thiacalix[4]arene fragments in cone, partial cone and 1,3-alternate conformations as their central core have been obtained. Their interaction with cations of s- and d-metals gives supramolecular assemblies whose composition depends on the conformation of pentakis-thiacalix[4]arenes and the nature of the ‘guests’. 相似文献
174.
Postnikov Eugene B. Pikalov Ivan Yu. Chora̧żewski Mirosław 《Journal of solution chemistry》2022,51(11):1311-1333
Journal of Solution Chemistry - Recently ionic liquids have been considered as prospective substances for application as heat transfer fluids, which requires accurate knowledge of their thermal... 相似文献
175.
Let denote a Hermite process of order and self-similarity parameter . This process is -self-similar, has stationary increments and exhibits long-range dependence. When , it corresponds to the fractional Brownian motion, whereas it is not Gaussian as soon as . In this paper, we deal with a Vasicek-type model driven by , of the form . Here, and are considered as unknown drift parameters. We provide estimators for and based on continuous-time observations. For all possible values of and , we prove strong consistency and we analyze the asymptotic fluctuations. 相似文献
176.
Alexander A. Larin Dr. Nikita V. Muravyev Prof. Dr. Alla N. Pivkina Dr. Kyrill Yu. Suponitsky Dr. Ivan V. Ananyev Dr. Dmitry V. Khakimov Dr. Leonid L. Fershtat Prof. Dr. Nina N. Makhova 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4225-4233
A series of highly energetic organic salts comprising a tetrazolylfuroxan anion, explosophoric azido or azo functionalities, and nitrogen-rich cations were synthesized by simple, efficient, and scalable chemical routes. These energetic materials were fully characterized by IR and multinuclear NMR (1H, 13C, 14N, 15N) spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). Additionally, the structure of an energetic salt consisting of an azidotetrazolylfuroxan anion and a 3,6,7-triamino-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazolium cation was confirmed by single-crystal X-ray diffraction. The synthesized compounds exhibit good experimental densities (1.57–1.71 g cm−3), very high enthalpies of formation (818–1363 kJ mol−1), and, as a result, excellent detonation performance (detonation velocities 7.54–8.26 kms−1 and detonation pressures 23.4–29.3 GPa). Most of the synthesized energetic salts have moderate sensitivity toward impact and friction, which makes them promising candidates for a variety of energetic applications. At the same time, three compounds have impact sensitivity on the primary explosives level (1.5–2.7 J). These results along with high detonation parameters and high nitrogen contents (66.0–70.2 %) indicate that these three compounds may serve as potential environmentally friendly alternatives to lead-based primary explosives. 相似文献
177.
178.
Ivan Bazhov 《Journal of Pure and Applied Algebra》2019,223(6):2530-2542
We study the similarities between the Fano varieties of lines on a cubic fourfold, a hyper-Kähler fourfold studied by Beauville and Donagi, and the hyper-Kähler fourfold constructed by Debarre and Voisin in [3]. We exhibit an analog of the notion of “triangle” for these varieties and prove that the 6-dimensional variety of “triangles” is a Lagrangian subvariety in the cube of the constructed hyper-Kähler fourfold. 相似文献
179.
180.