全文获取类型
收费全文 | 155篇 |
免费 | 2篇 |
专业分类
化学 | 71篇 |
晶体学 | 1篇 |
数学 | 15篇 |
物理学 | 70篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2019年 | 4篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 1篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 7篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 13篇 |
2007年 | 10篇 |
2006年 | 13篇 |
2005年 | 9篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有157条查询结果,搜索用时 46 毫秒
101.
Satoshi Kuriki Yoshiaki Harushima Hironori Fujisawa Nori Kurata 《Annals of the Institute of Statistical Mathematics》2014,66(4):725-757
In this study, we define a chi-square random field on a multi-dimensional lattice points index set with a direct product covariance structure and consider the distribution of the maximum of this random field. We provide two approximate formulas for the upper tail probability of the distribution based on nonlinear renewal theory and an integral-geometric approach called the volume-of-tube method. This study is motivated by the detection problem of the interactive loci pairs which play an important role in forming biological species. The joint distribution of scan statistics for detecting the pairs is regarded as the chi-square random field above, and hence the multiplicity-adjusted \(p\) -value can be calculated using the proposed approximate formulas. By using these formulas, we examine the data of Mizuta, Harushima and Kurata (Proc Nat Acad Sci USA 107(47):20417–20422, 2010) who reported a new interactive loci pair of rice inter-subspecies. 相似文献
102.
Eduardo José Crevelin Sarah Pigato Canova Itamar Soares Melo Tiago Domingues Zucchi Rafael Eduardo da Silva Luiz Alberto Beraldo Moraes 《Applied biochemistry and biotechnology》2013,171(7):1602-1616
Natural products produced by microorganisms have been utilized as sources of new drugs possessing a wide range of agrochemical and pharmacological activities. During our research on Actinomycetes from Brazilian mangroves, the ethyl acetate extract of Streptomyces sp. AMC 23 isolated from the red mangrove (Rhizophora mangle) rhizosphere produced a highly active compound against the microalga Chlorella vulgaris, often used to assess the phytotoxic activity. As a result, the bioassay-guided fractionation led to the isolation of the mixture of the known compounds bafilomycin B1 and bafilomycin B2. The chemical structures of bafilomycin B1 and bafilomycin B2 were established based on their spectroscopic data by infrared (IR), mass spectrometry (MS), 1H nuclear magnetic resonance (NMR), gradient-enhanced heteronuclear multiple quantum coherence (gHMQC), and gradient-enhanced heteronuclear multiple-bond connectivity (gHMBC) as well as comparison with reference data from the literature. Moreover, it was also possible to identify other bafilomycins using non-chromatographic-dependent techniques (Tandem mass spectrometry). Additionally, this is the first report on the phytotoxic activity of bafilomycin B1. 相似文献
103.
104.
105.
We propose an approach to coherently transfer populations between selected quantum states in one- and two-qubit systems by using controllable Stark-chirped rapid adiabatic passages. These evolution-time insensitive transfers, assisted by easily implementable single-qubit phase-shift operations, could serve as elementary logic gates for quantum computing. Specifically, this proposal could be conveniently demonstrated with existing Josephson phase qubits. Our proposal can find an immediate application in the readout of these qubits. Indeed, the broken parity symmetries of the bound states in these artificial atoms provide an efficient approach to design the required adiabatic pulses. 相似文献
106.
Graminha AE Rodrigues C Batista AA Teixeira LR Fagundes ES Beraldo H 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(4):1073-1076
Reaction of [RuCl(3)(dppb)H(2)O] (dppb=1,4 bis(diphenylphospine)butane) with 2-benzoylpyridine thiosemicarbazone (H2Bz4DH) and its N(4)-methyl (H2Bz4M) and N(4)-phehyl (H2Bz4Ph) derivatives gave [RuCl(dppb)(H2Bz4DH)]Cl (1), [RuCl(dppb)(H2Bz4M)]Cl (2) and [RuCl(dppb)(H2Bz4Ph)]Cl (3). The cytotoxic activity of the studied compounds was tested against the MCF-7, TK-10 and UACC-62 human tumor cell lines. The precursor [RuCl(3)(dppb)H(2)O] exhibits cytocidal activity against the tree cell lines. H2BzDH, H2Bz4M, and [RuCl(dppb)(H2Bz4M)]Cl (2) show a selective cytocidal effect against the UACC-62 cell line which makes them the most promising compounds. 相似文献
107.
We consider magnetic flux moving in superconductors with periodic pinning arrays. We show that sample heating by moving vortices produces negative differential resistivity (NDR) of both N and S type (i.e., N- and S-shaped) in the voltage-current characteristic (VI curve). The uniform flux flow state is unstable in the NDR region of the VI curve. Domain structures appear during the NDR part of the VI curve of an N type, while a filamentary instability is observed for the NDR of an S type. The simultaneous existence of the NDR of both types gives rise to the appearance of striking self-organized (both stationary and nonstationary) two-dimensional dynamical structures. 相似文献
108.
We propose a method to efficiently generate cluster states in charge qubits, both semiconducting and superconducting, as well as flux qubits. We show that highly entangled cluster states can be realized by a "one-touch" entanglement operation by tuning gate bias voltages for charge qubits. We also investigate the robustness of these cluster states for nonuniform qubits, which are unavoidable in solid-state systems. We find that quantum computation based on cluster states is a promising approach for solid-state qubits. 相似文献
109.
Lucius Flavius Ourives Bomfim Filho Cleidivania Rocha Bernardo Lages Rodrigues Heloisa Beraldo Leticia Regina Teixeira 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(7):1011-1020
In the present work, the two‐dimensional (2D) polymer poly[[μ4‐2‐(4‐nitrobenzenesulfonamido)benzoato‐κ4O1:O1:O1′:N6]silver(I)] (AgL), [Ag(C13H9N2O6S)]n, was obtained from 2‐(4‐nitrobenzenesulfonamido)benzoic acid (HL), C13H10N2O6S. FT–IR, 1H and 13C{1H} NMR spectroscopic analyses were used to characterize both compounds. The crystal structures of HL and AgL were determined by single‐crystal X‐ray diffraction. In the structure of HL, O—H…O hydrogen bonds between neighbouring molecules result in the formation of dimers, while the silver(I) complex shows polymerization associated with the O atoms of three distinct deprotonated ligands (L?). Thus, the structure of the Ag complex can be considered as a coordination polymer consisting of a one‐dimensional linear chain, constructed by carboxylate bridging groups, running parallel to the b axis. Neighbouring polymeric chains are further bridged by Ag—C monohapto contacts, resulting in a 2D framework. Fingerprint analysis of the Hirshfeld surfaces show that O…H/H…O hydrogen bonds are responsible for the most significant contacts in the crystal packing of HL and AgL, followed by the H…H and O…C/C…O interactions. The Ag…Ag, Ag…O/O…Ag and Ag…C/C…Ag interactions in the Hirshfeld surface represent 12.1% of the total interactions in the crystal packing. Studies of the interactions of the compounds with human serum albumin (HSA) indicated that both HL and AgL interact with HSA. 相似文献
110.
Maeda A Inoue Y Kitano H Savel'ev S Okayasu S Tsukada I Nori F 《Physical review letters》2005,94(7):077001
In analogy with the standard macroscopic friction, here we present a comparative study of the friction force felt by moving vortices in superconductors and charge density waves. Using experiments and a model for this data, our observations (1) provide a link between friction at the micro- and macroscopic scales, (2) explain the roundness of the static-kinetic friction transition in terms of thermal fluctuations, particle interactions, and system size (critical-phenomena view), and (3) explain the crossing of the kinetic friction F(k) versus velocity V for our pristine (high density of very weak defects) and our irradiated samples (with lower density of deeper pinning defects). 相似文献