全文获取类型
收费全文 | 2464篇 |
免费 | 95篇 |
国内免费 | 3篇 |
专业分类
化学 | 2106篇 |
晶体学 | 14篇 |
力学 | 37篇 |
数学 | 172篇 |
物理学 | 233篇 |
出版年
2024年 | 5篇 |
2023年 | 25篇 |
2022年 | 83篇 |
2021年 | 114篇 |
2020年 | 87篇 |
2019年 | 95篇 |
2018年 | 59篇 |
2017年 | 58篇 |
2016年 | 104篇 |
2015年 | 71篇 |
2014年 | 83篇 |
2013年 | 124篇 |
2012年 | 184篇 |
2011年 | 177篇 |
2010年 | 111篇 |
2009年 | 95篇 |
2008年 | 135篇 |
2007年 | 104篇 |
2006年 | 107篇 |
2005年 | 137篇 |
2004年 | 94篇 |
2003年 | 108篇 |
2002年 | 64篇 |
2001年 | 35篇 |
2000年 | 33篇 |
1999年 | 17篇 |
1998年 | 20篇 |
1997年 | 14篇 |
1996年 | 30篇 |
1995年 | 21篇 |
1994年 | 23篇 |
1993年 | 17篇 |
1992年 | 8篇 |
1991年 | 11篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1987年 | 6篇 |
1986年 | 10篇 |
1985年 | 7篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 11篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1969年 | 3篇 |
1916年 | 4篇 |
排序方式: 共有2562条查询结果,搜索用时 15 毫秒
101.
Prof. Richard D. Adams Dr. Poonam Dhull Matthew Pennachio Prof. Marina A. Petrukhina Dr. Mark D. Smith 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(16):4234-4239
The reaction of Re2(CO)8(μ-C6H5)(μ-H), 1 with corannulene (C20H10) yielded the product Re2(CO)8(μ-H)(μ-η2-1,2-C20H9), 2 (65 % yield) containing a Re2 metalated corannulene ligand formed by loss of benzene from 1 and the activation of one of the CH bonds of the nonplanar corannulene molecule by an oxidative-addition to 1 . The corannulenyl ligand has adopted a bridging η2-σ+π coordination to the Re2(CO)8 grouping. Compound 2 reacts with a second equivalent of 1 to yield three isomeric doubly metalated corannulene products: Re2(CO)8(μ-H)(μ-η2-1,2-μ-η2-10,11-C20H8)Re2(CO)8(μ-H), 3 (35 % yield), Re2(CO)8(μ-H)(μ-η2-2,1-μ-η2-10,11-C20H8)Re2(CO)8(μ-H), 4 (12 % yield), and Re2(CO)8(μ-H)(μ-η2-1,2-μ-η2-11,10-C20H8)Re2(CO)8(μ-H), 5 (12 % yield), by a second CH activation on a second rim double bond on the corannulene molecule. The isomers differ by the relative orientations of the coordinated Re2(CO)8(μ-H) groupings. All new products were characterized structurally by single crystal X-ray diffraction analysis. 相似文献
102.
Dmitry I. Bugaenko Alexey A. Volkov Dr. Mikhail V. Livantsov Prof. Dr. Marina A. Yurovskaya Dr. Alexander V. Karchava 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(54):12502-12506
The visible-light-induced arylation of tertiary phosphines with aryl(mesityl)iodonium triflates to produce the quaternary phosphonium salts occurs under mild, metal, and catalyst-free conditions. Photo-excited EDA complexes between diaryliodonium salts and phosphines supposedly enable this transformation, which is difficult to achieve through the traditional ground-state reactions. Demonstrating high functional group tolerance, broad scope, and complete selectivity of the aryl group transfer, the method is particularly compatible with sterically congested phosphines, which are challenging under metal-based catalytic methods. 相似文献
103.
104.
Dr. Shuangyan Wu Dr. Mingchang Zhu Dr. Ying Zhang Prof. Marina Kosinova Prof. Vladimir P. Fedin Prof. Enjun Gao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(14):3137-3144
As a hot topic of global concern, the distinguishing and detecting of antibiotic pollution is crucial owing to its adverse effect on ecosystems and human health stemming from excessive use and poor management. Herein, a water-stable lanthanide coordination polymer sensor (Dy-TCPB) with multiple emitting centers is prepared. The versatile Dy-TCPB can conveniently differentiate various antibiotics, and displays a self-calibration luminescent response to nitrofurazone (NFZ) and furazolidone (FZD). Each antibiotic exhibits notable correlation to a unique combination of the two ligand-to-Dy ion emission intensity ratios, enabling two-dimensional fingerprint recognition. Furthermore, the novel self-calibration sensor demonstrates effective recognition of NFZ and FZD with excellent sensitivity and selectivity, and detection limits as low as 0.0476 and 0.0482 μm for NFZ and FZD, respectively. The synthetic approach for the fabrication of a singular coordination polymer exhibiting multiple emissions provides a promising strategy for the development of facile and effective ratiometric sensors. 相似文献
105.
K10Ga3Bi6.65 is the first representative in the ternary system A-Ga-Bi (A = alkali metal). It contains [Ga3Bi6]9– anions with planar triangular-coordinated Ga atoms as the main structural feature, accompanied by isolated Bi–Bi dumbbells. Alkali metal cations are counterbalancing the charges and fill the space between the anionic units. According to the Zintl-Klemm concept charge balance is reached if an almost equal ratio of single and double-bonded Bi2 dumbbells are present according to (K+)10[Ga3Bi6]9–([Bi-Bi]4–)1/6([Bi=Bi]2–)1/6. 相似文献
106.
Nikita O. Shaparenko Nikolay B. Kompan'kov Marina G. Demidova Alexander I. Bulavchenko 《Electrophoresis》2020,41(18-19):1592-1599
The structure and conductivity of AOT (sodium bis(2-ethylhexyl) sulfosuccinate) solutions (2.5 × 10−4–2.5 × 10−1 M) in n-hexadecane-chloroform mixture at the chloroform concentration from 50 to 100 vol% were studied. The diffusion ordered spectroscopy NMR study revealed that in the indicated range, the observed hydrodynamic diameter of micelles depends only on the AOT concentration and does not depend on the chloroform content. Molar fractions of free AOT molecules and those aggregated into micelles were calculated using the Lindman's law: at concentrations above 2.5 × 10−1 М, the solutions contain mostly the micelles, whereas at concentrations below 2.5 × 10−4 M, the solutions contain AOT molecules. The transition region contains both the AOT molecules and the micelles. Conductivity measurements were used to determine free charge carriers in the bulk of solutions and their contributions to conductivity. 相似文献
107.
Nikolaos V. Tzouras Dr. Fady Nahra Dr. Laura Falivene Prof. Dr. Luigi Cavallo Marina Saab Prof. Dr. Kristof Van Hecke Dr. Alba Collado Dr. Christopher J. Collett Prof. Dr. Andrew D. Smith Prof. Dr. Catherine S. J. Cazin Prof. Dr. Steven P. Nolan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(20):4515-4519
We have been puzzled by the involvement of weak organic and inorganic bases in the synthesis of metal–N-heterocyclic carbene (NHC) complexes. Such bases are insufficiently strong to permit the presumed required deprotonation of the azolium salt (the carbene precursor) prior to metal binding. Experimental and computational studies provide support for a base-assisted concerted process that does not require free NHC formation. The synthetic protocol was found applicable to a number of transition-metal- and main-group-centered NHC compounds and could become the synthetic route of choice to form M–NHC bonds. 相似文献
108.
Dr. Lenka Štacková Marina Russo Dr. Lucie Muchová Vojtěch Orel Prof. Libor Vítek Dr. Peter Štacko Prof. Petr Klán 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(58):13184-13190
Carbon monoxide (CO) is an endogenous signaling molecule that controls a number of physiological processes. To circumvent the inherent toxicity of CO, light-activated CO-releasing molecules (photoCORMs) have emerged as an alternative for its administration. However, their wider application requires photoactivation using biologically benign visible and near-infrared (NIR) light. In this work, a strategy to access such photoCORMs by fusing two CO-releasing flavonol moieties with a NIR-absorbing cyanine dye is presented. These hybrids liberate two molecules of CO in high chemical yields upon activation with NIR light up to 820 nm and exhibit excellent uncaging cross-sections, which surpass the state-of-the-art by two orders of magnitude. Furthermore, the biocompatibility and applicability of the system in vitro and in vivo are demonstrated, and a mechanism of CO release is proposed. It is hoped that this strategy will stimulate the discovery of new classes of photoCORMs and accelerate the translation of CO-based phototherapy into practice. 相似文献
109.
Andreeva Marina Loza Natalia Kutenko Natalia Kononenko Natalia 《Journal of Solid State Electrochemistry》2020,24(1):101-110
Journal of Solid State Electrochemistry - A series of composites based on the perfluorinated MF-4SK membrane and polyaniline was obtained under electrodiffusion of monomer and oxidizer. Aniline was... 相似文献
110.
Spartak S. Khutsishvili Marina V. Lesnichaya Tamara I. Vakul’skaya Gania Dolmaa Galina P. Aleksandrova Aleksandr L. Rakevich 《光谱学快报》2018,51(4):169-173
Structural peculiarities and supramolecular organization of medicinally promising nanocomposites, synthesized from humic substances, which essentially differ depending on decomposition degree, have been studied using electron spin resonance, transmission electron, and confocal laser scanning microscopy techniques and some other modern physical–chemical methods. It is shown that stable zero-valent gold nanoparticle of about 10–17?nm in size are formed in a natural macromolecular matrix. The nanocomposites obtained turn out to be stable in aggregative state for a long time and preserve their properties that are extremely important for prospective medicinal substances. 相似文献