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An unidentified white powder collected as evidence in an intelligence investigation was characterized exclusively by nuclear magnetic resonance (NMR) analysis. A small fraction of the powder dissolved in D2O was subjected to a series of one- and two-dimensional techniques which were used to elucidate the molecular structure of the powder's major component and positively identify it as the scopolamine biotoxin. Quantitative one-dimensional experiments identified individual proton and carbon atom sites, and conventional 14N spectroscopy detected a single nitrogen atom site. Heteronuclear single quantum coherence data correlated all protons to their directly bonded carbon atom, and together with the quantitative spectra, were used to determine the number of protons directly bonded to each carbon atom. The presence of a methyl, carboxyl, and a benzyl group was also identified from these data. Correlation spectroscopy detected a three proton and a nine proton JH,H network, representing a CH2CH moiety and seven carbon atom ring, respectively. These five elements were assembled into an almost complete molecular structure by using long-range, J-coupled, 1H-13C pairs detected by heteronuclear multiple bond correlation (HMBC) spectroscopy and 1H-1H dipolar-coupled pairs found from nuclear Overhauser effect spectroscopy (NOESY) data. Additional oxygen atom sites were inferred from 1H-13C correlation intensities in the HMBC spectra along with 1H and 13C chemical shift values, or directly from NOESY correlations. Only a single oxygen atom site could not be inferred from NMR data, but its presence was inferred from comparisons to target analyte structures to complete the structure of the scopolamine molecule. To confirm these results, an ethanol/H2O solution of the powder was analyzed by direct infusion into an ion trap mass spectrometer. A prominent base signal was observed at m/z 304.1 amu, corresponding to the protonated molecular ion of scopolamine. Subsequently, the ion was selected and subjected to collision-induced dissociation, producing characteristic major MS/MS fragments at m/z 138.1 and 156.1. Comparisons of 1H and 13C chemical shift values and JH,H values measured from our NMR data were found to agree very favorably with previously reported values for scopolamine in D2O. 相似文献
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Jonathan Lewallen 《Regulation & Governance》2021,15(4):1035-1052
For governments to regulate, they must first define the problem and decide which policymakers have the authority to make decisions. Technological development can disrupt the authority-allocation process by fostering uncertainty about which actors are responsible for making policy. This article examines the role that changing technology has played in the development of cybersecurity policy in the United States. New technologies have increased the type and scope of assets vulnerable to cyberthreats, and with them the number of governing units who can claim jurisdiction over cybersecurity-related issues. Uncertainty about the nature of the problem has led the U.S. Congress to rely heavily on bureaucratic witnesses and focus on how existing regulations can be brought to bear. Emerging technologies create regulatory challenges for governance not only through unforeseen consequences but through uncertainty over who can regulate. Fragmented authority can produce piecemeal responses and a reliance on existing frameworks that benefit regulated industries. 相似文献
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Cole BL Wilhelm M Long PV Fielding JE Kominski G Morgenstern H 《Journal of health politics, policy and law》2004,29(6):1153-1186
Health impact assessment (HIA) has been advanced as a means of bringing potential health impacts to the attention of policy makers, particularly in sectors where health impacts may not otherwise be considered. This article examines lessons for HIA in the United States from the related and relatively well-developed field of environmental impact assessment (EIA). We reviewed the EIA literature and conducted twenty phone interviews with EIA professionals. Successes of EIA cited by respondents included integration of environmental goals into decision making, improved planning, and greater transparency and public involvement. Reported shortcomings included the length and complexity of EIA documents, limited and adversarial public participation, and an emphasis on procedure over substance. Presently, EIAs consider few, if any, health outcomes. Respondents differed on the prospects for HIA. Most agreed that HIA could contribute to EIA in several areas, including assessment of cumulative impacts and impacts to environmental justice. Reasons given for not incorporating HIA into EIA were uncertainties about interpreting estimated health impacts, that EIA documents would become even longer and more complicated, and that HIA would gain little from the procedural and legal emphasis in EIA. We conclude that for HIA to advance, whether as part of or separate from EIA, well-formulated methodologies need to be developed and tested in real-world situations. When possible, HIA should build on the methods that have been utilized successfully in EIA. The most fruitful avenue is demonstration projects that test, refine, and demonstrate different methods and models to maximize their utility and acceptance. 相似文献
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e-mail: wand{at}stanford.edu Testing the fit of competing equilibrium solutions to extensiveform games crucially depends on assumptions about the distributionof player types. To illustrate the importance of these assumptionsfor differentiating standard statistical models of strategicchoice, I draw on a game previously analyzed by Lewis and Schultz(2003). The differences that they highlight between a pair ofperfect Bayesian equilibrium and quantal response equilibriummodels are not produced by signaling and updating dynamics asclaimed, but are instead produced by different assumptions aboutthe distribution of player types. The method of analysis developedand the issues raised are applicable to a broad range of structuralmodels of conflict and bargaining. 相似文献