全文获取类型
收费全文 | 2005篇 |
免费 | 97篇 |
国内免费 | 4篇 |
专业分类
化学 | 1579篇 |
晶体学 | 4篇 |
力学 | 19篇 |
数学 | 211篇 |
物理学 | 293篇 |
出版年
2023年 | 21篇 |
2022年 | 51篇 |
2021年 | 55篇 |
2020年 | 36篇 |
2019年 | 41篇 |
2018年 | 26篇 |
2017年 | 29篇 |
2016年 | 61篇 |
2015年 | 65篇 |
2014年 | 67篇 |
2013年 | 113篇 |
2012年 | 107篇 |
2011年 | 119篇 |
2010年 | 76篇 |
2009年 | 58篇 |
2008年 | 107篇 |
2007年 | 116篇 |
2006年 | 102篇 |
2005年 | 91篇 |
2004年 | 87篇 |
2003年 | 65篇 |
2002年 | 52篇 |
2001年 | 27篇 |
2000年 | 16篇 |
1999年 | 24篇 |
1998年 | 22篇 |
1997年 | 15篇 |
1996年 | 25篇 |
1995年 | 20篇 |
1994年 | 22篇 |
1993年 | 29篇 |
1992年 | 29篇 |
1991年 | 16篇 |
1990年 | 21篇 |
1989年 | 14篇 |
1988年 | 10篇 |
1987年 | 27篇 |
1986年 | 20篇 |
1985年 | 8篇 |
1984年 | 17篇 |
1983年 | 11篇 |
1982年 | 16篇 |
1981年 | 14篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1974年 | 7篇 |
1971年 | 6篇 |
1970年 | 7篇 |
1928年 | 6篇 |
1923年 | 9篇 |
排序方式: 共有2106条查询结果,搜索用时 0 毫秒
101.
Michael G. Sommer Petra Kureljak Dr. Damijana Urankar Dr. David Schweinfurth Nikolina Stojanović Dr. Martina Bubrin Dr. Martin Gazvoda Dr. Maja Osmak Prof. Dr. Biprajit Sarkar Prof. Dr. Janez Košmrlj 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17296-17299
Azocarboxamide (azcH) has been combined for the first time with [Ru–Cym] to generate metal complexes with N,N‐ and N,O‐coordination mode, [(Cym)Ru(azc)Cl] and [(Cym)Ru(azcH)Cl]+[PF6]?. Geometric and electronic structures of the complexes are reported along with their in vitro activities against different tumour cell lines and preliminary results on solution chemistry. Compound [(Cym)Ru(azc)Cl] exhibited remarkable cytotoxic properties. It was cell‐type specific and had comparable IC50 values towards both cancer cells and their drug‐resistant subline. A tenfold increase in the sensitivity towards [(Cym)Ru(azc)Cl] was noted for the tumour cells with depleted intracellular glutathione (GSH) level, suggesting the essential role of GSH in cell response to this compound. 相似文献
102.
Dr. Yann Gloaguen Christophe Rebreyend Dr. Martin Lutz Pravin Kumar Dr. Martina Huber Dr. Ir. Jarl Ivar van der Vlugt Prof. Dr. Sven Schneider Prof. Dr. Bas de Bruin 《Angewandte Chemie (International ed. in English)》2014,53(26):6814-6818
Photochemical activation of [(PNNH)Rh(N3)] (PNNH=6‐di‐(tert‐butyl)phosphinomethyl‐2,2′‐bipyridine) complex 2 produced the paramagnetic (S=1/2), [(PNN)Rh?N.‐Rh(PNN)] complex 3 (PNN?=methylene‐deprotonated PNNH), which could be crystallographically characterized. Spectroscopic investigation of 3 indicates a predominant nitridyl radical (.N2?) character, which was confirmed computationally. Complex 3 reacts selectively with CO, producing two equivalents of [(PNN)RhI(CO)] complex 4 , presumably by nitridyl radical N,N‐coupling. 相似文献
103.
104.
105.
106.
Theodore Tyrikos-Ergas Eric T. Sletten Jhih-Yi Huang Peter H. Seeberger Martina Delbianco 《Chemical science》2022,13(7):2115
Sulfated glycans are involved in many biological processes, making well-defined sulfated oligosaccharides highly sought molecular probes. These compounds are a considerable synthetic challenge, with each oligosaccharide target requiring specific synthetic protocols and extensive purifications steps. Here, we describe a general on resin approach that simplifies the synthesis of sulfated glycans. The oligosaccharide backbone, obtained by Automated Glycan Assembly (AGA), is subjected to regioselective sulfation and hydrolysis of protecting groups. The protocol is compatible with several monosaccharides and allows for multi-sulfation of linear and branched glycans. Seven diverse, biologically relevant sulfated glycans were prepared in good to excellent overall yield.Well-defined sulfated oligosaccharides are important synthetic targets. We present an on resin approach for the synthesis of sulfated glycans with a broad reaction scope that overcomes previous limitations associated with on resin synthesis. 相似文献
107.
108.
Natalia Calonghi Carla Boga Patrizia Nitti Dario Telese Silvia Bordoni Giovanna Farruggia Fioretta Asaro Martina Grandi Chiara Zalambani Gabriele Micheletti 《Molecules (Basel, Switzerland)》2022,27(8)
A series of regioisomers of the hydroxystearic acid (HSA) was prepared, and the effect of the position of the hydroxyl group along the chain on a panel of human cancer cell lines was investigated. Among the various regioisomers, those carrying the hydroxyl at positions 5, 7, and 9 had growth inhibitor activity against various human tumor cell lines, including CaCo-2, HT29, HeLa, MCF7, PC3, and NLF cells. 10-HSA and 11-HSA showed a very weak effect. 8-HSA did not show inhibitory activity in all cell lines. The biological role of 7-HSA and 9-HSA is widely recognized, while little is known about the effects of 5-HSA. Therefore, the biological effects of 5-HSA in HeLa, HT29, MCF7, and NLF cell lines were investigated using the Livecyte’s ptychography technology, which allows correlating changes in proliferation, motility, and morphology as a function of treatment at the same time. 5-HSA not only reduces cell proliferation but also induces changes in cell displacement, directionality, and speed. It is important to characterize the biological effects of 5-HSA, this molecule being an important component of fatty acyl esters of hydroxy fatty acids (FAHFA), a class of endogenous mammalian lipids with noticeable anti-diabetic and anti-inflammatory effects. 相似文献
109.
The present paper is the second and main part of a study of partial differential equations under the influence of noisy perturbations. Existence and uniqueness of function solutions in the mild sense are obtained for a class of deterministic linear and semilinear parabolic boundary initial value problems. If the noise data are random, the results may be seen as a pathwise approach to SPDE's. For typical examples, such as spatially one-dimensional stochastic heat equations with additive or multiplicative perturbations of fractional Brownian type, we recover and extend known results. In addition, we propose to consider partial noises of low order. 相似文献
110.
Hubert Hřebabecký Milan Dejmek Martin Dračínský Michal Šála Pieter Leyssen Johan Neyts Martina Kaniaková Jan Krůšek Radim Nencka 《Tetrahedron》2012,68(4):1286-1298
Azanorbornylpurine derivatives were prepared by Mitsunobu reaction of appropriate hydroxyazanorbornane derivative with 6-chloropurine or construction of purine base at azanorbornylamines. The prepared target compounds were evaluated for antiviral activity and effect on neuronal and muscle nicotinic acetylcholine receptors. 相似文献