全文获取类型
收费全文 | 228篇 |
免费 | 2篇 |
专业分类
化学 | 89篇 |
晶体学 | 9篇 |
力学 | 11篇 |
数学 | 51篇 |
物理学 | 70篇 |
出版年
2019年 | 2篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 8篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1994年 | 2篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 7篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 6篇 |
1974年 | 8篇 |
1973年 | 15篇 |
1972年 | 5篇 |
1971年 | 4篇 |
1970年 | 2篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1966年 | 1篇 |
1907年 | 1篇 |
1890年 | 1篇 |
排序方式: 共有230条查询结果,搜索用时 15 毫秒
171.
Brendan Gleeson James Claffey Daniel Ertler Megan Hogan Helge Müller-Bunz Francesca Paradisi Denise Wallis Matthias Tacke 《Polyhedron》2008,27(18):3619-3624
From the reaction of 6-(p-methoxyphenyl) fulvene (1a), 6-(p-N,N-dimethylaminophenyl) fulvene (1b) and 6-(3,4-dimethoxyphenyl) fulvene (1c) with LiBEt3H, lithiated cyclopentadienide intermediates (2a–c) were synthesised. These intermediates were then transmetallated to tin with SnCl4 to yield tetra-substituted bis(cyclopentadienyl)tin dichloride complexes (3a–c). Further reaction with tin tetrachloride yielded the benzyl-substituted derivatives bis-[(p-methoxybenzyl)cyclopentadienyl] tin(IV) dichloride (4a), bis-[(p-N,N-dimethylaminobenzyl)cyclopentadienyl] tin(IV) dichloride (4b), and bis-[(3,4-dimethoxyphenyl)cyclopentadienyl] tin(IV) dichloride (4c). Preliminary antibacterial tests were carried out using the Kirby–Bauer disk-diffusion method, in which 4a–c showed little to no activity against the Gram-negative bacterium Escherichia coli, but medium activity against Gram-positive bacteria (MRSA, MSSA). In addition, the organotin complexes had their cytotoxicity investigated through preliminary in vitro testing on the LLC-PK (pig kidney epithelial) cell line in order to determine their IC50 values. Compound 4c showed no cytotoxic activity, while 4a and 4b were found to have IC50 values of 15 and 205 μM, respectively. 相似文献
172.
A simple criterion for the transition from stratified flow to the slug or plug flow regime in horizontal rectangular ducts is presented. A theoretical model is developed and shown to be consistent with data obtained by blowing air over stationary water in channels with a wide range of geometrical parameters. Some data for cocurrent and countercurrent flow are also correlated successfully. 相似文献
173.
In powder mixtures of ZnO and TiO2 the compounds Zn2TiO4, ZnTiO3 and Zn2Ti3O8 can be formed as a result of solid state reactions. The mechanism of the double oxide formation is essentially determined by the microstructure of the powder mixture. Furthermore, the kind of the double oxide depends on the TiO2-modification. There exist structural similarities between Zn2TiO4 (spinel) and TiO2 (anatase) on the one hand and ZnTiO3 and TiO2 (rutile) on the other hand. The compound Zn2Ti3O8 is formed only on the basis of the Zn2TiO4-phase. The crystal structure of Zn2Ti3O8 was derived as a defect spinel. The unoccupied sites of cations are not arranged statistically, but they are ordered in the structure. This order leads to the decrease of the space group symmetry from Fd-3 m to P4332. 相似文献
174.
175.
Sh. K. Nasibullaev Yu. V. Vasil’ev R. R. Abzalimov A. S. Lobach I. O. Bashkin D. Wallis T. Drewello 《Physics of the Solid State》2002,44(3):551-553
This paper reports on the results of mass spectrometric and theoretical investigations of hydrogenated and deuterated fullerene derivatives C60H(D)x. The formation and decay (through electron autodetachment) of negative molecular ions of the C60H18 and C60D18 hydrofullerenes are discussed. A comparative analysis of these processes is performed for different fullerene derivatives. 相似文献
176.
Becer CR Gibson MI Geng J Ilyas R Wallis R Mitchell DA Haddleton DM 《Journal of the American Chemical Society》2010,132(43):15130-15132
Noncovalent interactions between complex carbohydrates and proteins drive many fundamental processes within biological systems, including human immunity. In this report we aimed to investigate the potential of mannose-containing glycopolymers to interact with human DC-SIGN and the ability of these glycopolymers to inhibit the interactions between DC-SIGN and the HIV envelope glycoprotein gp120. We used a library of glycopolymers that are prepared via combination of copper-mediated living radical polymerization and azide-alkyne [3+2] Huisgen cycloaddition reaction. We demonstrate that a relatively simple glycopolymer can effectively prevent the interactions between a human dendritic cell associated lectin (DC-SIGN) and the viral envelope glycoprotein gp120. This approach may give rise to novel insights into the mechanisms of HIV infection and provide potential new therapeutics. 相似文献
177.
Brendan Gleeson James Claffey Megan Hogan Helge Müller-Bunz Denise Wallis Matthias Tacke 《Journal of organometallic chemistry》2009,694(9-10):1369-1374
From the reaction of 6-(p-methoxyphenyl) fulvene (1a), 6-(3,4-dimethoxyphenyl) fulvene (1b) and 6-(3,4,5-trimethoxyphenyl) fulvene (1c) with LiBEt3H, lithiated cyclopentadienide intermediates (2a–c) were synthesised. These intermediates were then transmetallated to vanadium with VCl4 to yield the benzyl-substituted vanadocenes bis-[(p-methoxybenzyl)cyclopentadienyl] vanadium(IV) dichloride (3a), bis-[(3,4-dimethoxybenzyl)cyclopentadienyl] vanadium(IV) dichloride (3b), and bis-[(3,4,5-trimethoxybenzyl)cyclopentadienyl] vanadium(IV) dichloride (3c). The two vanadocenes 3a and 3c were characterised by single crystal X-ray diffraction. All three vanadocenes had their cytotoxicity investigated through MTT based preliminary in vitro testing on the LLC-PK (pig kidney epithelial) cell line in order to determine their IC50 values and compare them with the corresponding titanocene dichloride derivatives. Vanadocenes 3b–c were found to have IC50 values of 9.1 and 8.3 μM, while 3a showed a superior value of 3.0 μM, respectively. 相似文献
178.
Jennifer Wallis 《Aequationes Mathematicae》1973,9(2-3):306-306
179.
Shintu Mathew Xian Zhou Gerald Münch Francis Bodkin Matthew Wallis Feng Li Ritesh Raju 《Molecules (Basel, Switzerland)》2022,27(19)
Inspired by ethnopharmacological knowledge, we conducted a bioassay-guided fractionation of the leaves of Tristaniopsis laurina which led to the discovery of a new anti-inflammatory compound, tristaenone A (1). The structure was elucidated by detailed spectroscopic data analysis, and the absolute configuration was established using X-ray crystallography analysis. Tristaenone A (1) suppressed LPS and IFN-γ-induced NO, TNF-α and IL-6 production in RAW 264.7 cells with IC50 values of 37.58 ± 2.45 μM, 80.6 ± 5.82 μM and 125.65 ± 0.34 μM, respectively. It also inhibited NF-κB nuclear translocation by 52.93 ± 14.14% at a concentration of 31.85 μM. 相似文献
180.