全文获取类型
收费全文 | 164篇 |
免费 | 2篇 |
专业分类
化学 | 115篇 |
力学 | 9篇 |
数学 | 7篇 |
物理学 | 35篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 3篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 14篇 |
2012年 | 2篇 |
2011年 | 6篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 11篇 |
2007年 | 15篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 12篇 |
2003年 | 6篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 2篇 |
排序方式: 共有166条查询结果,搜索用时 15 毫秒
51.
Electron hopping conductivity and vapor sensing properties of flexible network polymer films of metal nanoparticles 总被引:2,自引:0,他引:2
Zamborini FP Leopold MC Hicks JF Kulesza PJ Malik MA Murray RW 《Journal of the American Chemical Society》2002,124(30):8958-8964
Films of monolayer protected Au clusters (MPCs) with mixed alkanethiolate and omega-carboxylate alkanethiolate monolayers, linked together in a network polymer by carboxylate-Cu2+-carboxylate bridges, exhibit electronic conductivities (sigma(EL)) that vary with both the numbers of methylene segments in the ligands and the bathing medium (N2, liquid or vapor). A chainlength-dependent swelling/contraction of the film's internal structure is shown to account for changes in sigma(EL). The linker chains appear to have sufficient flexibility to collapse and fold with varied degrees of film swelling or dryness. Conductivity is most influenced (exponentially dependent) by the chainlength of the nonlinker (alkanethiolate) ligands, a result consistent with electron tunneling through the alkanethiolate chains and nonbonded contacts between those chains on individual, adjacent MPCs. The sigma(EL) results concur with the behavior of UV-vis surface plasmon adsorption bands, which are enhanced for short nonlinker ligands and when the films are dry. The film conductivities respond to exposure to organic vapors, decreasing in electronic conductivity and increasing in mass (quartz crystal microgravimetry, QCM). In the presence of organic vapor, the flexible network of linked nanoparticles allows for a swelling-induced alteration in either length or chemical nature of electron tunneling pathways or both. 相似文献
52.
Cuello-Nuñez Susana Benning Jocelyn Liu Chuan Branton Peter Hu Jin McAdam Kevin G. Coburn Steven Braybrook Julian Goenaga-Infante Heidi 《Analytical and bioanalytical chemistry》2018,410(26):6795-6806
Analytical and Bioanalytical Chemistry - Fractionation data for cadmium in tobacco products, as obtained by sequential leaching of cadmium species with ICP-MS/MS analysis, and separately by X-ray... 相似文献
53.
Richard C. Remsing Jocelyn M. Rodgers John D. Weeks 《Journal of statistical physics》2011,145(2):313-334
Using concepts from perturbation and local molecular field theories of liquids we divide the potential of the SPC/E water
model into short and long ranged parts. The short ranged parts define a minimal reference network model that captures very
well the structure of the local hydrogen bond network in bulk water while ignoring effects of the remaining long ranged interactions.
This deconstruction can provide insight into the different roles that the local hydrogen bond network, dispersion forces,
and long ranged dipolar interactions play in determining a variety of properties of SPC/E and related classical models of
water. Here we focus on the anomalous behavior of the internal pressure and the temperature dependence of the density of bulk
water. We further utilize these short ranged models along with local molecular field theory to quantify the influence of these
interactions on the structure of hydrophobic interfaces and the crossover from small to large scale hydration behavior. The
implications of our findings for theories of hydrophobicity and possible refinements of classical water models are also discussed. 相似文献
54.
The Australian Fiberscopic Profile (AFP) was developed for use in a previous study of normal voices to provide standard documentation for examining the larynx under continuous light. The AFP is being used currently in five specialized voice clinics in Australia to collect data on dysphonic voices. After use with 40 clients it became obvious that a revision with clearer definitions of the parameters was needed to make it a more useful clinical tool. 相似文献
55.
56.
Wei Zhang Liban Jirmo Samira Toledo‐Roy Prof. John C. Hershberger Jocelyn M. Macho Prof. Alexander J. Grenning 《Angewandte Chemie (International ed. in English)》2016,55(51):15792-15796
Oxygenated, polycyclic terpenoid natural products have important biological activities. Although total synthesis of such terpenes is widely studied, synthetic strategies that allow for controlled placement of oxygen atoms and other functionality remains a challenge. Herein, we present a simple, scalable, and tunable synthetic strategy to assemble terpenoid‐like polycycloalkanes from cycloalkanones, malononitrile, and allylic electrophiles, abundantly available reagent classes. 相似文献
57.
Stereospecific synthesis of the sex pheromone of the passionvine mealybug, Planococcus minor 总被引:1,自引:0,他引:1
Jocelyn G. Millar 《Tetrahedron letters》2008,49(2):315-317
A short and completely stereospecific synthesis of (E)-2-isopropyl-5-methyl-2,4-hexadienyl acetate, the very recently identified sex pheromone of the passionvine mealybug Planococcus minor, is described. In the key step, CuI-catalyzed anti-addition of a Grignard reagent to a propargyllic alcohol intermediate gave the required trisubstituted alkene with 100% regio- and stereospecificity. The stereochemical purity of the pheromone is critically important because the (Z)-isomer is a powerful behavioral antagonist. 相似文献
58.
Jocelyn C. Bruce Klaus R. Koch 《Acta Crystallographica. Section C, Structural Chemistry》2008,64(1):m1-m4
The crystal and molecular structures of N‐benzoyl‐N′,N′‐dibutylselenourea (HL), C16H24N2OSe, and the corresponding complex bis(N‐benzoyl‐N′,N′‐dibutylselenoureato‐κ2Se,O)palladium(II), [Pd(C16H23N2OSe)2], are reported. The selenourea molecule is characterized by intermolecular hydrogen bonds between the selenoamidic H atom and the Se atom of a neighbouring molecule forming a dimer, presumably as a consequence of resonance‐assisted hydrogen bonding or π‐bonding co‐operativity. A second dimeric hydrogen bond is also described. In the palladium complex, the typical square‐planar coordination characteristic of such ligands results in a cis‐[Pd(L‐Se,O)2] complex. 相似文献
59.
Nucleoside 5'-triphosphates (NTPs) play key roles in biology and medicine. However, these compounds are notoriously difficult to synthesize. We describe a one-pot method to prepare NTPs from nucleoside 5'-H-phosphonate monoesters via pyridinium phosphoramidates, and we used this approach to synthesize ATP, UTP, GTP, CTP, ribavirin-TP, and 6-methylpurine ribonucleoside-TP (6MePTP). Poliovirus RNA-dependent RNA polymerase efficiently employed 6MePTP as a substrate, suggesting that the cognate nucleoside, a poorly understood antiviral agent, may damage viral RNA. 相似文献
60.
Dr. Ilia Kochetygov Jocelyn Roth Dr. Jordi Espín Sophia Pache Dr. Anita Justin Till Schertenleib Dr. Nazanin Taheri Dr. Dmitry Chernyshov Prof. Wendy L. Queen 《Angewandte Chemie (International ed. in English)》2023,62(16):e202215595
The design of metal–organic frameworks (MOFs) having large pore sizes and volumes often requires the use of complex organic ligands, currently synthesized using costly and time-consuming palladium-catalyzed coupling chemistry. Thus, in the present work, a new strategy for ligand design is reported, where piperazine and dihydrophenazine units are used as substitutes for benzene rings, which are the basic building block of most MOF ligands. This chemistry, which is based on simple, nucleophilic aromatic substitution (SNAr) reactions, is used for the transition metal catalyst-free construction of 21 new, carboxylate-based ligands with varying sizes, shapes, and denticity and 15 linear di- and tetra-nitriles. Moreover, to demonstrate the utility of the ligands as building blocks, 16 new structurally diverse MOFs having surface areas up to 3100 m2 g−1 were also synthesized. 相似文献