全文获取类型
收费全文 | 6514篇 |
免费 | 270篇 |
国内免费 | 35篇 |
专业分类
化学 | 4560篇 |
晶体学 | 117篇 |
力学 | 111篇 |
综合类 | 1篇 |
数学 | 794篇 |
物理学 | 1236篇 |
出版年
2023年 | 53篇 |
2022年 | 34篇 |
2021年 | 83篇 |
2020年 | 161篇 |
2019年 | 154篇 |
2018年 | 88篇 |
2017年 | 88篇 |
2016年 | 192篇 |
2015年 | 198篇 |
2014年 | 198篇 |
2013年 | 275篇 |
2012年 | 377篇 |
2011年 | 443篇 |
2010年 | 247篇 |
2009年 | 254篇 |
2008年 | 389篇 |
2007年 | 402篇 |
2006年 | 385篇 |
2005年 | 357篇 |
2004年 | 296篇 |
2003年 | 206篇 |
2002年 | 183篇 |
2001年 | 90篇 |
2000年 | 81篇 |
1999年 | 59篇 |
1998年 | 63篇 |
1997年 | 73篇 |
1996年 | 95篇 |
1995年 | 94篇 |
1994年 | 55篇 |
1993年 | 62篇 |
1992年 | 62篇 |
1991年 | 52篇 |
1990年 | 65篇 |
1989年 | 46篇 |
1988年 | 46篇 |
1987年 | 48篇 |
1986年 | 41篇 |
1985年 | 58篇 |
1984年 | 45篇 |
1983年 | 41篇 |
1982年 | 35篇 |
1981年 | 52篇 |
1980年 | 49篇 |
1979年 | 26篇 |
1978年 | 35篇 |
1977年 | 38篇 |
1976年 | 31篇 |
1973年 | 42篇 |
1971年 | 27篇 |
排序方式: 共有6819条查询结果,搜索用时 93 毫秒
101.
102.
Simon Rohrbach Andrew J. Smith Jia Hao Pang Darren L. Poole Tell Tuttle Shunsuke Chiba John A. Murphy 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(46):16518-16540
Jüngste Entwicklungen in der experimentellen und theoretischen Chemie haben zur Identifizierung einer schnell wachsenden Klasse von nukleophilen aromatischen Substitutionsreaktionen geführt, die einem konzertierten Mechanismus (cSNAr) folgen, und nicht dem klassischen, zweistufigen SNAr‐Mechanismus. Während klassische SNAr‐Reaktionen auf die substantielle Aktivierung des aromatischen Ringes durch elektronenziehende Substituenten angewiesen sind, ist eine solche Aktivierung für den konzertierten Reaktionsverlauf nicht zwingend nötig. 相似文献
103.
Dr. Marion Daniel-Bertrand Sébastien Garcia-Argote Dr. Alberto Palazzolo Dr. Irene Mustieles Marin Dr. Pier-Francesco Fazzini Dr. Simon Tricard Dr. Bruno Chaudret Dr. Volker Derdau Dr. Sophie Feuillastre Dr. Grégory Pieters 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21300-21306
Radiolabelling is fundamental in drug discovery and development as it is mandatory for preclinical ADME studies and late-stage human clinical trials. Herein, a general, effective, and easy to implement method for the multiple site incorporation of deuterium and tritium atoms using the commercially available and air-stable iridium precatalyst [Ir(COD)(OMe)]2 is described. A large scope of pharmaceutically relevant substructures can be labelled using this method including pyridine, pyrazine, indole, carbazole, aniline, oxa-/thia-zoles, thiophene, but also electron-rich phenyl groups. The high functional group tolerance of the reaction is highlighted by the labelling of a wide range of complex pharmaceuticals, containing notably halogen or sulfur atoms and nitrile groups. The multiple site hydrogen isotope incorporation has been explained by the in situ formation of complementary catalytically active species: monometallic iridium complexes and iridium nanoparticles. 相似文献
104.
105.
106.
107.
Rapid Generation and Safe Use of Carbenes Enabled by a Novel Flow Protocol with In‐line IR spectroscopy 下载免费PDF全文
Simon T. R. Müller Aurélien Murat Delphine Maillos Dr. Patrick Lesimple Dr. Paul Hellier Prof. Dr. Thomas Wirth 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(19):7016-7020
A powerful new continuous process for the formation and use of donor/acceptor‐substituted carbenes is described. The safety profile of diazo group transfer on methyl phenylacetate was determined including kinetic studies in batch and in flow using in‐line IR analysis. Batch work‐up and liquid chromatography were circumvented by developing an optimized liquid/liquid flow separation method providing aryl diazoacetates in high purity. Fast screening of reaction conditions in flow with in‐line IR analysis allowed rapid reaction optimization. Finally, a multistep process of diazo group transfer, extraction, separation and subsequent diazo decomposition combined with multiple X?H insertion reactions was established. 相似文献
108.
109.
Re‐Appearance of Cooperativity in Ultra‐Small Spin‐Crossover [Fe(pz){Ni(CN)4}] Nanoparticles 下载免费PDF全文
Haonan Peng Dr. Simon Tricard Gautier Félix Dr. Gábor Molnár Dr. William Nicolazzi Dr. Lionel Salmon Dr. Azzedine Bousseksou 《Angewandte Chemie (International ed. in English)》2014,53(41):10894-10898
A reverse nanoemulsion technique was used for the elaboration of [Fe(pz){Ni(CN)4}] nanoparticles. Low‐temperature micellar exchange made it possible to elaborate ultra‐small nanoparticles with sizes down to 2 nm. When decreasing the size of the particles from 110 to 12 nm the spin transition shifts to lower temperatures, becomes gradual, and the hysteresis shrinks. On the other hand, a re‐opening of the hysteresis was observed for smaller (2 nm) particles. A detailed 57Fe Mössbauer spectroscopy analysis was used to correlate this unusual phenomenon to the modification of the stiffness of the nanoparticles thanks to the determination of their Debye temperature. 相似文献
110.
Mark A. Newton Marco Di Michiel Davide Ferri Marcos Fernàndez-Garcia Andrew M. Beale Simon D. M. Jacques Peter J. Chupas Karena W. Chapman 《Catalysis Surveys from Asia》2014,18(4):134-148
Very high energy X-rays (ca. >40 keV) have long offered great promise in providing great insight into the inner workings of catalysts; insights that may complement the battery of techniques available to researchers in catalysis either in the laboratory or at more conventional X-ray wavelengths. This contribution aims to critically assess the diverse possibilities now available in the high energy domain as a result of the maturation of third generation synchrotron facilities and to look forward to the potential that forthcoming developments in synchrotron source technology may offer the world of catalysis in the near future. 相似文献