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排序方式: 共有449条查询结果,搜索用时 15 毫秒
441.
W.T. Lim J.S. Wright R. Khanna Jae-Soung Park Joon-Hyung Lee D.P. Norton 《Applied Surface Science》2007,253(23):9228-9233
The dry etching characteristics of bulk, single-crystal zinc-oxide (ZnO) and rf-sputtered indium-zinc-oxide (IZO) films have been investigated using an inductively coupled high-density plasma with different plasma chemistries. The introduction of interhalogens such as ICl, IBr, BI3, and BBr3 to the Ar plasma produced no enhancement of the ZnO and IZO etch rates with respect to physical sputtering in a pure argon atmosphere under the same experimental conditions. In these plasma chemistries, the etch rate of both materials increased with source power and ion energy, indicating that ion bombardment plays an important role in enhancing desorption of etch products. Except in Ar/CH4/H2 discharges, the ZnO etch rate was very similar to that of IZO, which indicates that zinc and indium atoms are driven by a similar plasma etching dynamic. CH4/H2-containing plasmas produced higher etch rates for IZO than for ZnO due to the preferential desorption of the group III etch products. Application of the CH4/H2/Ar plasma to the etching of deep features in bulk, single-crystal ZnO produced highly anisotropic profiles although some trenches were observed near the sidewalls. 相似文献
442.
Khlifi M Nollet M Paillous P Bruston P Raulin F Bénilan Y Khanna RK 《Journal of Molecular Spectroscopy》1999,194(2):206-210
Laboratory spectral data (peak positions and integrated band intensities) of the infrared bands of acrylonitrile (CH2CHCN) gas in the region 4000-220 cm-1 are presented. Even though CH2CHCN has not yet been identified in Titan's atmosphere, it is among the possible photochemical and cosmic irradiation products of CH4 + N2 chemistry in the atmosphere of Titan. Laboratory simulations of Titan's atmospheric chemistry also give CH2CHCN as a product species. The results of our evaluation of the infrared intensity data provide an upper limit of the stratospheric abundance of CH2CHCN. Copyright 1999 Academic Press. 相似文献
443.
R.P. Patil S.S. Gaikwad A.N. Karanjekar P.K. Khanna G.H. Jain V.B. Gaikwad P.V. More N. Bisht 《Materials Today Chemistry》2020
In this study, we comprehensively present the gas sensing performance of strontium (Sr)-doped barium titanate (BaTiO3) nanostructures which are synthesized by a low-temperature hydrothermal route. The in-situ doping of strontium in BaTiO3 nanostructures is achieved with different molar concentrations of Sr, and the sensing performance was evaluated by screen printing process of products to form their thick films. The thick films of as-prepared Sr-doped BaTiO3 (BaSrTiO3) were investigated for gas sensing performance for various gases at different operating temperatures where strong response was observed for both nitrogen dioxide (NO2) and ammonia (NH3) gases at room temperature. Furthermore, the sensing response at room temperature for NH3 and NO2 gases was also studied with respect to Sr doping concentrations in BaTiO3 nanostructures. 相似文献
444.
Deployment of heterogeneous wireless networks is spreading throughout the world as users want to be connected anytime, anywhere, and anyhow. Meanwhile, users are increasingly interested in multimedia applications such as audio, video streaming and Voice over IP (VoIP), which require strict Quality of Service (QoS) support. Provisioning of Always Best Connected (ABC) network with such constraints is a challenging task. Considering the availability of various access technologies, it is difficult for a network operator to find reliable criteria to select the best network that ensures user satisfaction while reducing multiple network selection. Designing an efficient Network selection algorithm, in this type of environment, is an important research problem. In this paper, we propose a novel network selection algorithm utilizing signal strength, available bit rate, signal to noise ratio, achievable throughput, bit error rate and outage probability metrics as criteria for network selection. The selection metrics are combined with PSO for relative dynamic weight optimization. The proposed algorithm is implemented in a typical heterogeneous environment of EDGE (2.5G) and UMTS (3G). Switching rate of the user between available networks has been used as the performance metric. Moreover, a utility function is used to maintain desired QoS during transition between networks, which is measured in terms of the throughput. It is shown here that PSO based approach yields optimal network selection in heterogeneous wireless environment. 相似文献
445.
Network selection algorithm based on link quality parameters for heterogeneous wireless networks 总被引:2,自引:0,他引:2
Next generation wireless networks consist of heterogeneous access technologies. In order to provide global ubiquitous communication, it is required to provide a framework in which user can move across multiple access interfaces while maintaining its ongoing communication at perceived quality of service. Given the scenario of multiple access networks, it is further required to select the optimum network out of multiple candidate networks to meet the requirements of the ongoing session. The selection of optimum network in such heterogeneous environment is generally based on network conditions and user preference. In this paper, we propose an algorithm for network selection based on averaged received signal strength, outage probability and distance. The proposed algorithm comprises of two stages. Assuming that network conditions are dominant in network selection, in first stage, overlapping region is identified through distance estimation. Network selection algorithm based on averaged received signal strength plus outage is invoked in second stage to select the optimum network. Numerical results are obtained through a simulation model of two disparate networks – GSM and UMTS. It has been shown that the proposed algorithm offers 68% improved performance in terms of network selection rate. 相似文献
446.
P. K. Khanna 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):951-955
Abstract The organic chemistry of 1,2,3-selenadiazoles has been explored to a greater extent due to the fact that the chemistry of 1,2,3-selenadiazoles mostly is driven by its facile decomposition via elimination of a nitrogen molecule and formation of selenaketocarben and/or its dimerization to 1,4-diselenin. The reactions of 1,2,3-selenadiazoles directly with various transition metal compounds have resulted in unique organo-selenium transition metal complexes. However, the materials chemistry of 1,2,3-selenadiazoles has not appeared in literature prior to the first publication on the subject from our laboratory in 2003. To, the best of our knowledge, no research group is engaged in such an activity. We, have exclusively explored the potential of 1,2,3-selenadiazoles for their effective utilization in synthesis of semiconductor nano particles or nano powder and in this lecture, the results and methodology for the same would be discussed. 相似文献
447.
Köster AM Calaminici P Orgaz E Roy DR Reveles JU Khanna SN 《Journal of the American Chemical Society》2011,133(31):12192-12196
First-principles electronic structure calculations within a gradient corrected density functional formalism have been carried out to investigate the electronic structure and magnetic properties of Pd(13) clusters. It is shown that a bilayer ground-state structure that can be regarded as a relaxed bulk fragment is most compatible with the experimental results from Stern-Gerlach measurements. An icosahedral structure, considered to be the ground state in numerous previous studies, is shown to be around 0.14 eV above the ground state. A detailed analysis of the molecular orbitals reveals the near degeneracy of the bilayer or icosahedral structures is rooted in the stabilization by p- or d-like cluster orbitals. The importance of low-lying spin states in controlling the electronic and magnetic properties of the cluster is highlighted. 相似文献
448.
Pawan K. Khanna Christopher P. Morley Michael B. Hursthouse K. M. Abdul Malik Oliver W. Howarth 《Heteroatom Chemistry》1995,6(6):519-524
Treatment of tetrakis(triphenylphosphine)platinum with elemental selenium (red or vitreous) in toluene solution under reflux yields an insoluble solid. This dissolves in dichloromethane with reaction, eventually to form a 1 : 1 mixture of [PtCl2(PPh3)2] and the new compound [Pt(Se2CH2)(PPh3)2], which has been characterized by multinuclear NMR spectroscopy and X-ray crystallography. Under the same conditions, tetrakis(triphenylphosphine)-palladium yields only decomposition products. © John Wiley & Sons, Inc. 相似文献
449.
J. Ulises Reveles Patrizia Calaminici Marcela R. Beltran Andres M. Koester Shiv N. Khanna 《ChemInform》2008,39(16):no-no
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献