全文获取类型
收费全文 | 3856篇 |
免费 | 111篇 |
国内免费 | 21篇 |
专业分类
化学 | 2254篇 |
晶体学 | 22篇 |
力学 | 239篇 |
数学 | 771篇 |
物理学 | 702篇 |
出版年
2023年 | 22篇 |
2022年 | 44篇 |
2021年 | 64篇 |
2020年 | 63篇 |
2019年 | 68篇 |
2018年 | 48篇 |
2017年 | 58篇 |
2016年 | 125篇 |
2015年 | 105篇 |
2014年 | 110篇 |
2013年 | 228篇 |
2012年 | 244篇 |
2011年 | 232篇 |
2010年 | 161篇 |
2009年 | 137篇 |
2008年 | 223篇 |
2007年 | 231篇 |
2006年 | 186篇 |
2005年 | 172篇 |
2004年 | 197篇 |
2003年 | 150篇 |
2002年 | 155篇 |
2001年 | 51篇 |
2000年 | 37篇 |
1999年 | 42篇 |
1998年 | 43篇 |
1997年 | 47篇 |
1996年 | 57篇 |
1995年 | 45篇 |
1994年 | 44篇 |
1993年 | 34篇 |
1992年 | 38篇 |
1991年 | 30篇 |
1990年 | 30篇 |
1989年 | 18篇 |
1988年 | 35篇 |
1987年 | 27篇 |
1986年 | 22篇 |
1985年 | 44篇 |
1984年 | 39篇 |
1983年 | 31篇 |
1982年 | 33篇 |
1981年 | 31篇 |
1980年 | 27篇 |
1979年 | 30篇 |
1978年 | 20篇 |
1977年 | 16篇 |
1976年 | 16篇 |
1975年 | 15篇 |
1974年 | 17篇 |
排序方式: 共有3988条查询结果,搜索用时 15 毫秒
181.
Generic applications of 13C‐detected NMR diffusion to formulated systems with suppression of thermal convection induced by proton decoupling 下载免费PDF全文
Jianbo Hou Yiyong He Paolo Sabatino Ling Yuan David Redwine 《Magnetic resonance in chemistry : MRC》2016,54(7):584-591
Fast and effective structural/compositional analysis on formulated systems represents one of the major challenges encountered in analytical science. 13C‐detected diffusion represents a promising tool to tackle the aforementioned challenges, particularly in industry. Toward exploring the generic applications of 13C‐detected diffusion, thermal convection induced by 1H decoupling has been identified as a key factor that resulted in significantly reduced resolution in the diffusion dimension. Optimization of experimental parameters and utilization of double‐stimulated echo‐based pulse sequence both can effectively suppress the thermal convection caused by the 1H decoupling, the success of which allows robust and generic applications of 13C‐detected diffusion to systems from mixtures of small molecules, polymer blends, and copolymers to actual complex formulated systems. The method is particularly powerful in differentiating small molecules from polymers, polymer blends from copolymers, and end‐group analysis. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
182.
183.
Paolo Ferruti 《Journal of polymer science. Part A, Polymer chemistry》2013,51(11):2319-2353
Poly(amidoamine)s (PAAs) are a family of synthetic polymers obtained by stepwise polyaddition of prim‐ or sec‐amines to bisacrylamides. Nearly all conceivable bisacrylamides and prim‐ or sec‐amines can be employed as monomers endowing PAAs of a structural versatility nearly unique among stepwise polyaddition polymers. PAAs are degradable in aqueous media, including physiological fluids. Many of them are remarkably biocompatible notwithstanding their cationic character. PAAs are per se highly functional polymers and, in addition, can be further functionalized giving rise to an endless variety of polymeric structures meeting the requisites for applications in such apparently disparate fields as inorganic water pollutants scavengers, sensors, drug and protein intracellular carriers, transfection promoters, peptidomimetic antiviral and antimalarial agents. In this review, the unique chemistry of PAAs is discussed and a vast library of PAA structures and PAA applications from the beginning to the present days reported. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2319–2353 相似文献
184.
Nera Cagnoli Paolo Ceccherelli Massimo Curini Maria Carla Marcotullio Ernest Wenkert 《合成通讯》2013,43(11):1261-1271
Copper oxide-catalyzed decomposition of 1-diazoacetyl-1-methyl-3-methylenecyclohexanes produces strained tricycles whose reduction or hydrolysis affords 6-bicyclo[3.2.1]octanones. 相似文献
185.
Enrico Le Donne Gian Paolo Leonardi Roberto Monti Davide Vittone 《Geometric And Functional Analysis》2013,23(4):1371-1401
We classify extremal curves in free nilpotent Lie groups. The classification is obtained via an explicit integration of the adjoint equation in Pontryagin maximum principle. It turns out that abnormal extremals are precisely the horizontal curves contained in algebraic varieties of a specific type. We also extend the results to the nonfree case. 相似文献
186.
187.
Marcello Bernardara Emanuele Macrì Sukhendu Mehrotra Paolo Stellari 《Advances in Mathematics》2012,229(2):770-803
We prove a categorical version of the Torelli theorem for cubic threefolds. More precisely, we show that the non-trivial part of a semi-orthogonal decomposition of the derived category of a cubic threefold characterizes its isomorphism class. 相似文献
188.
189.
190.