全文获取类型
收费全文 | 36206篇 |
免费 | 1351篇 |
国内免费 | 25篇 |
专业分类
化学 | 24555篇 |
晶体学 | 332篇 |
力学 | 646篇 |
数学 | 5058篇 |
物理学 | 6991篇 |
出版年
2023年 | 282篇 |
2022年 | 244篇 |
2021年 | 418篇 |
2020年 | 587篇 |
2019年 | 564篇 |
2018年 | 764篇 |
2017年 | 703篇 |
2016年 | 1332篇 |
2015年 | 1105篇 |
2014年 | 1114篇 |
2013年 | 2316篇 |
2012年 | 2446篇 |
2011年 | 2623篇 |
2010年 | 1548篇 |
2009年 | 1279篇 |
2008年 | 2225篇 |
2007年 | 2121篇 |
2006年 | 1897篇 |
2005年 | 1697篇 |
2004年 | 1389篇 |
2003年 | 1070篇 |
2002年 | 982篇 |
2001年 | 732篇 |
2000年 | 659篇 |
1999年 | 494篇 |
1998年 | 363篇 |
1997年 | 286篇 |
1996年 | 431篇 |
1995年 | 307篇 |
1994年 | 300篇 |
1993年 | 329篇 |
1992年 | 297篇 |
1991年 | 208篇 |
1990年 | 210篇 |
1989年 | 172篇 |
1988年 | 167篇 |
1987年 | 162篇 |
1986年 | 162篇 |
1985年 | 243篇 |
1984年 | 210篇 |
1983年 | 174篇 |
1982年 | 176篇 |
1981年 | 157篇 |
1980年 | 137篇 |
1979年 | 150篇 |
1978年 | 150篇 |
1977年 | 145篇 |
1976年 | 159篇 |
1975年 | 138篇 |
1973年 | 145篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Mejía Hugo Fernando Giraldo Jiménez-Piqué Emilio Valdés Matías Procaccini Raúl Pellice Sergio 《Journal of Solid State Electrochemistry》2020,24(10):2451-2460
Journal of Solid State Electrochemistry - A novel material was developed using sol-gel chemistry and an environmental-friendly grafting process of clay nanoparticles. In a previous work of our... 相似文献
32.
Synthesis,Electronic Properties and WOLED Devices of Planar Phosphorus‐Containing Polycyclic Aromatic Hydrocarbons
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)
Dr. François Riobé Rózsa Szűcs Dr. Pierre‐Antoine Bouit Dr. Denis Tondelier Bernard Geffroy Fátima Aparicio Julia Buendía Prof. Luis Sánchez Prof. Régis Réau Prof. László Nyulászi Prof. Muriel Hissler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(17):6547-6556
We describe the synthesis and the physical properties of polyaromatic hydrocarbons (PAHs) containing a phosphorus atom at the edge. In particular, the impact of the successive addition of aromatic rings on the electronic properties was investigated by experimental (UV/Vis absorption, fluorescence, cyclic voltammetry) and theoretical studies (DFT). The physical properties recorded in solution and in the solid state showed that the P‐containing PAHs exhibit properties expected for an emitter in white organic light‐emitting diodes (WOLEDs). 相似文献
33.
34.
35.
Highly Selective Copper‐Catalyzed Asymmetric [3+2] Cycloaddition of Azomethine Ylides with Acyclic 1,3‐Dienes
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)
María González‐Esguevillas Ana Pascual‐Escudero Dr. Javier Adrio Prof. Dr. Juan C. Carretero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12):4561-4565
The first examples of the catalytic asymmetric 1,3‐dipolar cycloaddition of azomethine ylides with acyclic activated 1,3‐dienes (and 1,3‐enynes) are described. Under copper catalysis, a selective cycloaddition at the terminal γ,δ‐C?C bond is observed. In addition, depending on the ligand used, either the exo or the endo adduct can be obtained with high selectivity. Under appropriate reaction conditions, the acyclic 1,6‐addition product is detected, suggesting a stepwise mechanism. The resulting C4‐alkenyl‐substituted pyrrolidines are suitable substrates for further access to polycyclic systems, as highlighted by the preparation of hexahydrochromeno[4,3‐b]pyrrole and the tetracyclic core of the alkaloid gracilamine. 相似文献
36.
37.
38.
39.
Lubomír Kubáček 《Applications of Mathematics》2006,51(6):565-582
Some remarks to problems of point and interval estimation, testing and problems of outliers are presented in the case of multivariate
regression model.
This work was supported by the Council of Czech Government J14/98:153100011. 相似文献
40.
Ricardo Celorrio Vı́ctor Domínguez Francisco-Javier Sayas 《Comptes Rendus Mathematique》2002,334(10):923-926
In this work we study the solution of Laplace's equation in a domain with holes by an iteration consisting of splitting the problem in an exterior one, around the holes, plus an interior problem in the unholed domain. We show the existence of a decomposition of the solution when the exterior problem is represented by means of a single-layer protential. Also, for the three-dimensional case and with some adjustments for the two-dimensional case, we prove convergence of the method by writing the iteration as a Jacobi iteration for an operator equation and studying the spectrum of the iteration operator. To cite this article: R. Celorrio et al., C. R. Acad. Sci. Paris, Ser. I 334 (2002) 923–926. 相似文献