全文获取类型
收费全文 | 179篇 |
免费 | 3篇 |
专业分类
化学 | 103篇 |
晶体学 | 7篇 |
力学 | 2篇 |
数学 | 13篇 |
物理学 | 57篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 8篇 |
2013年 | 9篇 |
2012年 | 4篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 8篇 |
2006年 | 7篇 |
2005年 | 3篇 |
2002年 | 2篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1970年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有182条查询结果,搜索用时 15 毫秒
151.
Mamata Singh Manoj K. Bharty Aarti Singh Sujata Kashyap Udai P. Singh Nand K. Singh 《Transition Metal Chemistry》2012,37(8):695-703
Two new Mn(II) complexes [Mn(Hmbhce)2(o-phen)] (1) and [Mn(Hmbhce)2(bpy)] (2) based on N??-(2-methoxybenzoyl)hydrazine carbodithioic acid ethyl ester (H2mbhce) have been synthesized by reacting Mn(OAc)2·4H2O with H2mbhce in the presence of o-phen/bpy. The complexes have been characterized by elemental analyses, magnetic susceptibility measurement, IR, UV?CVis and single crystal X-ray data. Both complexes [Mn(Hmbhce)2(o-phen)] and [Mn(Hmbhce)2(bpy)] crystallize in monoclinic system with space group P 21/c and P 21/n, respectively. The single crystal X-ray structures of 1 and 2 show that the Mn(II) center is bonded with two (Hmbhce)? through carbonyl oxygen and deprotonated hydrazinic nitrogen, plus two nitrogen atoms from one o-phen/bpy co-ligand. The crystal structures of complexes 1 and 2 are stabilized by weak intramolecular N?CH···O hydrogen bonding and C?CH···?? interactions giving supramolecular architectures. 相似文献
152.
Mohd Zaheeruddin Beg Shraddha Tivari Akanksha Kashyap Pravin K. Singh Praveen P. Singh Pankaj Nainwal Vishal Srivastava 《Journal of heterocyclic chemistry》2024,61(3):458-465
An efficient visible light-mediated, eosin Y-catalyzed synthesis of oxazole has been developed from benzil with primary amines, that providing a straightforward, green, and environmentally benign access to a wide variety of substituted oxazole-2-amines under mild reaction conditions. 相似文献
153.
AbstractIn this study, dense fine-grained ZrB2 and TiB2 were fabricated using reactive spark plasma sintering (RSPS) of ball-milled Zr/B and Ti/B mixtures. Systematic investigations were carried out to understand the mechanisms of reactive sintering. Two densification mechanisms were found to be operating during RSPS. The first stage of densification was due to self-propagating high temperature synthesis reaction leading to formation of ZrB2 and TiB2 compacts having relative density of ~48 and ~65%, respectively. The second stage of densification occurred at temperatures more than 1100 °C and resulted in final relative density of more than 98%. Electron backscatter diffraction and electron microscopy studies on interrupted RSPS samples as well as dense samples showed deformed grains and presence of slip steps while grain orientation spread map and pole figure analysis confirmed plastic flow. Plastic flow-aided pore closure is shown as major mechanism during reactive sintering. 相似文献
154.
Aïssa Harhira Francis Guay Maxime Daigle Raman Kashyap 《Optics Communications》2010,283(23):4633-4638
A new holographic technique is proposed for fabricating long-period fiber gratings (LPGs) using a CO2-laser and a phase mask. A CO2 laser operating at 10.6 μm is incident normally on the phase mask and the diffracted interfering beams imprint a thermally induced periodic modulation into the cladding of the fiber placed behind the mask. Preliminary results of this technique are presented and discussed. An unusual self-tapered fiber LPG (STFLPG) is also presented. 相似文献
155.
156.
157.
158.
159.
Recent extension of mean spherical approximation (MSA) for electrolyte solution has been employed to investigate the non-ideality
in Born-free energy of solvation of a rigid, mono-positive ion in binary dipolar mixtures of associating (ethanol-water) and
non-associating (dimethylsulfoxide-acetonitrile) solvents. In addition to the dipole moments, the solvent size ratio and ion
size have been treated in a consistent manner in this extended MSA theory for the first time. The solvent-solvent size ratio
is found to play an important role in determining the non-ideality in these binary mixtures. Smaller ions such as Li+ and Na+ show stronger non-ideality in such mixtures compared to bigger ions (for example, Cs+ and Bu4N+). The partial solvent polarization densities around smaller ions in tertiary butanol (TBA)-water mixture is found to be very
different from that in other alcohol-water mixtures as well as to that for larger ions in aqueous solutions of TBA. Non-ideality
is weaker in mixtures consisting of solvent species possessing nearly equal diameters and dipole moments and is reflected
in the mole fraction dependent partial solvent polarization densities. 相似文献
160.
We present a new theoretical scheme for Yb3+-doped athermal (radiation-balanced) continuous-wave fiber amplifier. This approach allows amplification with optical pumping of the fiber amplifier without detrimental heating of the fiber. Athermal amplification is realized by laser cooling in which waste heat is disposed of in the form of spontaneous fluorescence by balancing the radiated and absorbed power. The radiation-balanced fiber amplification can be realized using a specially designed distributed pumping scheme. 相似文献