全文获取类型
收费全文 | 930篇 |
免费 | 1篇 |
国内免费 | 6篇 |
专业分类
化学 | 750篇 |
力学 | 35篇 |
数学 | 96篇 |
物理学 | 56篇 |
出版年
2022年 | 8篇 |
2021年 | 10篇 |
2020年 | 7篇 |
2019年 | 5篇 |
2016年 | 12篇 |
2015年 | 10篇 |
2014年 | 8篇 |
2013年 | 28篇 |
2012年 | 39篇 |
2011年 | 53篇 |
2010年 | 29篇 |
2009年 | 19篇 |
2008年 | 45篇 |
2007年 | 46篇 |
2006年 | 49篇 |
2005年 | 51篇 |
2004年 | 52篇 |
2003年 | 43篇 |
2002年 | 31篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 11篇 |
1998年 | 17篇 |
1997年 | 20篇 |
1996年 | 22篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 14篇 |
1992年 | 18篇 |
1991年 | 17篇 |
1990年 | 16篇 |
1989年 | 9篇 |
1988年 | 15篇 |
1987年 | 10篇 |
1986年 | 6篇 |
1985年 | 12篇 |
1984年 | 11篇 |
1983年 | 11篇 |
1982年 | 9篇 |
1981年 | 11篇 |
1980年 | 14篇 |
1979年 | 14篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 15篇 |
1974年 | 8篇 |
1973年 | 16篇 |
1972年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有937条查询结果,搜索用时 15 毫秒
931.
Thierry Cassagne Henri‐Jean Cristau Grard Delmas Michel Desgranges Claude Lion Gilbert Magnaud liane Torreilles David Virieux 《Heteroatom Chemistry》2001,12(6):485-490
Reactions of O‐ethyl S‐(2‐diisopropyl‐amino)ethyl methylphosphonothiolate, VX 1 , were investigated with five oxidizing agents. In all the cases, the formation of the VX N‐oxide 7 was observed prior to the subsequent oxidation and hydrolysis into the nontoxic O‐ethyl methylphosphonate 2. Magnesium monoperoxyphthalate (MMPP) is probably one of the most active reagents to achieve the complete detoxification of VX 1 . The decontamination using MMPP was also extended with success to soman 13 , a G‐type agent. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:485–490, 2001 相似文献
932.
Margherita Burattini Robrecht Lippens Nicolas Baleine Melanie Gerard Joeri Van Meerssche Chloë Geeroms Jérémy Odent Jean-Marie Raquez Sandra Van Vlierberghe Lieven Thorrez 《Macromolecular bioscience》2023,23(7):2300019
For tissue engineering of skeletal muscles, there is a need for biomaterials which do not only allow cell attachment, proliferation, and differentiation, but also support the physiological conditions of the tissue. Next to the chemical nature and structure of the biomaterial, its response to the application of biophysical stimuli, such as mechanical deformation or application of electrical pulses, can impact in vitro tissue culture. In this study, gelatin methacryloyl (GelMA) is modified with hydrophilic 2-acryloxyethyltrimethylammonium chloride (AETA) and 3-sulfopropyl acrylate potassium (SPA) ionic comonomers to obtain a piezoionic hydrogel. Rheology, mass swelling, gel fraction, and mechanical characteristics are determined. The piezoionic properties of the SPA and AETA-modified GelMA are confirmed by a significant increase in ionic conductivity and an electrical response as a function of mechanical stress. Murine myoblasts display a viability of >95% after 1 week on the piezoionic hydrogels, confirming their biocompatibility. The GelMA modifications do not influence the fusion capacity of the seeded myoblasts or myotube width after myotube formation. These results describe a novel functionalization providing new possibilities to exploit piezo-effects in the tissue engineering field. 相似文献
933.
A diradical initiator containing two thermoreversible bonds was prepared and used for the polymerization of styrene at 90°C. The monomer consumption and the variation of the molecular weight were monitored with time. The results show that the process can be considered as living and that the polymerization rate is independent of the radical initiator concentration. By elemental analysis of the chain ends it was concluded that the propagation reaction occurs at both ends. 相似文献
934.
Alejandro J. Müller Julio Albuerne Luis M. Esteves Leni Marquez Jean-Marie Raquez Philippe Degée Philippe Dubois Stephen Collins Ian W. Hamley 《Macromolecular Symposia》2004,215(1):369-382
The morphology, crystallization and self nucleation behavior of double crystalline diblock copolymers of poly(p-dioxanone) (PPDX) and poly(ϵ-caprolactone) (PCL) with different compositions have been studied by different techniques, including optical microscopy (OM), atomic force microscopy (AFM) and differential scanning calorimetry (DSC). The two blocks crystallize in a single coincident exotherm when cooled from the melt. The self-nucleation technique is able to separate into two exotherms the crystallization of each block. We have gathered evidences indicating that the PPDX block can nucleate the PCL block within the copolymers regardless of the composition. This effect is responsible for the lack of homogeneous nucleation or fractionated crystallization of the PCL block even when it constitutes a minor phase within the copolymer (25% or less). Nevertheless, we were able to show that decreasing amounts of PCL within the diblock copolymer still produces confinement effects that retard the crystallization kinetics of the PCL component and decrease the Avrami index. On the other hand evidence for confinement was also obtained for the PPDX block, since as its content is reduced within the copolymer, a depression in its self-nucleation and annealing temperatures were observed. 相似文献
935.
The reaction of 4,5-dimethyl-2-phenylphosphinine with sulfur in boiling benzene in the presence of N-methylimidazole as a catalyst first yields a P-sulfide. This monosulfide further reacts with sulfur to give a diphosphinine trisulfide and a diphosphinine tetrasulfide. The X-ray crystal structure analysis of the trisulfide has been carried out. The two head-to-tail 1,6-dihydrophosphinine rings are connected by P S C and P C links, thus forming a central 1,2,4-thiadiphospholane heterocycle. The P C bridge is weak [1.881(3) Å] and sulfur can insert into it to give the symmetrical tetrasulfide with two P S C bridges. 相似文献
936.
937.