全文获取类型
收费全文 | 10263篇 |
免费 | 452篇 |
国内免费 | 29篇 |
专业分类
化学 | 6542篇 |
晶体学 | 134篇 |
力学 | 400篇 |
综合类 | 1篇 |
数学 | 1831篇 |
物理学 | 1836篇 |
出版年
2024年 | 16篇 |
2023年 | 77篇 |
2022年 | 91篇 |
2021年 | 138篇 |
2020年 | 227篇 |
2019年 | 209篇 |
2018年 | 323篇 |
2017年 | 279篇 |
2016年 | 464篇 |
2015年 | 338篇 |
2014年 | 431篇 |
2013年 | 939篇 |
2012年 | 709篇 |
2011年 | 756篇 |
2010年 | 466篇 |
2009年 | 394篇 |
2008年 | 681篇 |
2007年 | 676篇 |
2006年 | 554篇 |
2005年 | 484篇 |
2004年 | 360篇 |
2003年 | 334篇 |
2002年 | 288篇 |
2001年 | 127篇 |
2000年 | 106篇 |
1999年 | 92篇 |
1998年 | 75篇 |
1997年 | 58篇 |
1996年 | 93篇 |
1995年 | 72篇 |
1994年 | 59篇 |
1993年 | 52篇 |
1992年 | 45篇 |
1991年 | 37篇 |
1990年 | 26篇 |
1989年 | 27篇 |
1987年 | 27篇 |
1985年 | 55篇 |
1984年 | 43篇 |
1983年 | 20篇 |
1982年 | 53篇 |
1981年 | 43篇 |
1980年 | 52篇 |
1979年 | 47篇 |
1978年 | 34篇 |
1977年 | 29篇 |
1976年 | 47篇 |
1975年 | 43篇 |
1974年 | 28篇 |
1973年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Synthesis,Electronic Properties and WOLED Devices of Planar Phosphorus‐Containing Polycyclic Aromatic Hydrocarbons 下载免费PDF全文
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
5.
6.
7.
Beyond Stereoselectivity,Switchable Catalysis: Some of the Last Frontier Challenges in Ring‐Opening Polymerization of Cyclic Esters 下载免费PDF全文
Dr. Sophie M. Guillaume Dr. Evgueni Kirillov Dr. Yann Sarazin Prof. Dr. Jean‐François Carpentier 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):7988-8003
Metal‐based catalysts and initiators have played a pivotal role in the ring‐opening polymerization (ROP) of cyclic esters, thanks to their high activity and remarkable ability to control precisely the architectures of the resulting polyesters in terms of molar mass, dispersity, microstructure, or tacticity. Today, after two decades of extensive research, the field is slowly reaching maturity. However, several challenges remain, while original concepts have emerged around new types or new applications of catalysis. This Review is not intended to comprehensively cover all of these aspects. Rather, it provides a personal overview of the very recent progress achieved in some selected, important aspects of ROP catalysis—stereocontrol and switchable catalysis. Hence, the first part addresses the development of new metal‐based catalysts for the isoselective ROP of racemic lactide towards stereoblock copolymers, and the use of syndioselective ROP metal catalysts to control the monomer sequence in copolymers. A second part covers the development of ROP catalysts—primarily metal‐based catalysts, but also organocatalysts—that can be externally regulated by the use of chemical or photo stimuli to switch them between two states with different catalytic abilities. Current challenges and opportunities are highlighted. 相似文献
8.
9.
10.
J. C. Fabris S. V. B. Gonçalves P. E. de Souza 《General Relativity and Gravitation》2002,34(12):2111-2126
The mass power spectrum for a Universe dominated by the Chaplygin gas is evaluated numerically from scales of the order of the Hubble horizon to 100 Mpc. The results are compared with a pure baryonic Universe and a cosmological constant model. In all three cases, the spectrum increases with k, the wavenumber of the perturbations. The slope of the spectrum is higher for the baryonic model and smaller for the cosmological constant model, the Chaplygin gas interpolating these two models. The results are analyzed in terms of the sound velocity of the Chaplygin gas and the moment the Universe begins to accelerate. 相似文献