全文获取类型
收费全文 | 171篇 |
免费 | 5篇 |
国内免费 | 3篇 |
专业分类
化学 | 87篇 |
晶体学 | 4篇 |
力学 | 3篇 |
数学 | 68篇 |
物理学 | 17篇 |
出版年
2023年 | 3篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 5篇 |
2011年 | 12篇 |
2010年 | 3篇 |
2009年 | 6篇 |
2008年 | 3篇 |
2007年 | 10篇 |
2006年 | 5篇 |
2005年 | 16篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 5篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有179条查询结果,搜索用时 15 毫秒
171.
172.
Brian A. Davey 《Algebra Universalis》2013,70(4):403-409
This note aims to unravel the history of the Product Representation Theorem for Interlaced Pre-bilattices. We will see that it has its lattice-theoretic roots in early attempts to solve one of the problems in Birkhoff’s Lattice Theory. The theorem was presented in its full generality by Czédli, Huhn and Szabó at a conference in Szeged, Hungary in 1980 (and published in 1983). This was several years before Ginsberg introduced bilattices at a conference on artificial intelligence in 1986 and in his foundational paper in 1988. 相似文献
173.
The development and optimization of on-line microdistillation for free and total sulfite (S(IV)) in grape juice and wine is reported. The microstill used both heat and an air stream to separate sulfur dioxide from the wine samples; the distillation product was captured in a peroxide solution, and converted to sulfuric acid, mirroring accepted industry practice. Measured from 1 to 300 mg L−1 as SO2 by conductance, sample throughputs of 60 h−1 for free and 20 h−1 for total sulfite were achieved. Data for bound S(IV) emphasises the slow kinetics of release reactions in some wines. The microstill method is more efficient for total sulfite than the accepted manual technique. Good correlation was found between the microstill and manual methods under specified control conditions. 相似文献
174.
A cascade radical-mediated Diels-Alder reaction with the iododienynone 16b produced the tricyclic ketone 17 (22%). By contrast, treatment of the substituted furans 36 and 47 with Bu(3)SnH-AIBN, instead led to the tetracycles 44 and 58 respectively, rather than the anticipated oestranes, i.e. 38 and 48. In a separate study, attempted cascade radical-mediated cyclisations from the ortho-aryl substituted iododienynones 72 and 73, leading to the ring-D aromatic steroid 7, instead gave the macrocyclic ketone 76 or the novel bridged tricycles 77/82, respectively, depending on whether benzene or heptane was used as solvent in the reactions. 相似文献
175.
Dr. Haobo Li Prof. Yan Jiao Prof. Kenneth Davey Prof. Shi-Zhang Qiao 《Angewandte Chemie (International ed. in English)》2023,62(9):e202216383
The design of heterogeneous catalysts is necessarily surface-focused, generally achieved via optimization of adsorption energy and microkinetic modelling. A prerequisite is to ensure the adsorption energy is physically meaningful is the stable existence of the conceived active-site structure on the surface. The development of improved understanding of the catalyst surface, however, is challenging practically because of the complex nature of dynamic surface formation and evolution under in-situ reactions. We propose therefore data-driven machine-learning (ML) approaches as a solution. In this Minireview we summarize recent progress in using machine-learning to search and predict (meta)stable structures, assist operando simulation under reaction conditions and micro-environments, and critically analyze experimental characterization data. We conclude that ML will become the new norm to lower costs associated with discovery and design of optimal heterogeneous catalysts. 相似文献
176.
JJ Bryant Y Zhang BD Lindner EA Davey AL Appleton X Qian UH Bunz 《The Journal of organic chemistry》2012,77(17):7479-7486
We have synthesized a series of ethynylated phenazines and their bis-triazolyl cycloadducts to serve as metal ion sensors. Binding of metal ions is achieved through coordination to the phenazine nitrogen atom and the triazole ring. To allow metal sensing in aqueous solution, the triazole units are substituted with water-soluble ethylene glycol chains. These phenazine cycloadducts exhibit a selective affinity for binding silver ions. Examination of the halogenated analogues reveals a lowering of the band gap and the corresponding bathochromic shifts in the absorption and emission spectra. The electron-withdrawing properties of these halogens also result in significantly decreased metal-binding activity of the phenazine cycloadducts. 相似文献
177.
178.
The velocity and shape of growth layers on the {100} faces of ammonium dihydrogen phosphate (ADP) crystals growing in aqueous solution at pH = 5.0 are compared with those previously reported for growth at pH = 3.8. The results are interpreted in terms of the adsorption of hydrated hydroxonium ions on the crystal surface. 相似文献
179.
Ammonium dihydrogen phosphate (ADP) crystals develop new high index faces when grown from aqueous solution containing up to 1000 ppm of added CrCl3 · 6 H2O. The crystallographic nature of these faces has been studied as a function of the CrCl3 · 6 H2O concentration in the growth solution (24.0°C, σ = 0.06) and their high morphological importance is explained, using a modification of the Hartman-Perdok theory of crystal morphology, but postulating that the adsorption of impurity species at specific sites transform K-faces into pseudo-F-faces. 相似文献