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61.
6-Monoacetylmorphine (6-MAM) is a good indicator for the intake of heroin and can be detected in blood, urine and hair of heroin users. A new radioimmunoassay (RIA) designed specifically for 6-monoacetylmorphine (6-MAM) was tested for its usefulness for the quantitation of the drug in urine, serum and hair. Its cross-reactivity with heroin and its metabolites, and related compounds was also determined. Eighty-nine hair, six serum and 25 urine samples where 6-MAM had been previously identified by GC/MS were analysed for 6-MAM with the new RIA kit. A good correlation existed between the GC/MS and RIA results for the hair samples. However, the amount of 6-MAM found in serum and urine differed considerably between the two methods. This difference could be explained by the cross-reactivity of the antibody with morphine and morphine-6-glucuronide, which are present in much larger amounts in serum and urine, than in hair. To evaluate a new rationalisation procedure, some hair samples were split into two portions after incubation. One part was analyzed for 6-MAM by RIA, and the other portion by GC/MS. 相似文献
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63.
This paper estimates risk reductions for each layer of security designed to prevent commercial passenger airliners from being commandeered by terrorists, kept under control for some time, and then crashed into specific targets. Probabilistic methods are used to characterize the uncertainty of rates of deterrence, detection, and disruption, as well as losses. Since homeland security decisionmakers tend to be risk‐averse because of the catastrophic or dire nature of the hazard or event, utility theory and Monte Carlo simulation methods are used to propagate uncertainties in calculations of net present value, expected utility, and probabilities of net benefit. We employ a “break‐even” cost‐benefit analysis to determine the minimum probability of an otherwise successful attack that is required for the benefit of security measures to equal their cost. In this context, we examine specific policy options: including Improvised Physical Secondary Barriers (IPSBs) in the array of aircraft security measures, including the Federal Air Marshal Service (FAMS), and including them both. Attack probabilities need to exceed 260 percent or 2.6 attacks per year to be 90 percent sure that FAMS is cost‐effective, whereas IPSBs have more than 90 percent chance of being cost‐effective even if attack probabilities are as low as 6 percent per year. A risk‐neutral analysis finds a policy option of adding IPSBs but not FAMS to the other measures to be preferred for all attack probabilities. However, a very risk‐averse decisionmaker is 48 percent likely to prefer to retain FAMS even if the attack probability is as low as 1 percent per year—a level of risk aversion exhibited by few, if any, government agencies. Overall, it seems that, even in an analysis that biases the consideration toward the opposite conclusion, far too much may currently be spent on security measures to address the problem of airline hijacking, and many spending reductions could likely be made with little or no consequent reduction of security. 相似文献
64.
This paper presents the results of a regression analysis of the market structure determinants of profitability among the Brazilian and Mexican manufacturing affiliates of US multinational corporations. The study employs data on 206 firms derived from a special survey specifically designed to obtain detailed information on their market structure environments and performance characteristics. Our estimates confirm that seller concentration, product differentiation, and relative market share are three sources of market power of these firms. Despite the many economic and noneconomic differences between Brazil and Mexico, there are no systematic differences between the two in their underlying structure‐performance relationships. 相似文献
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66.
Dennis C. Mueller 《Public Choice》2012,152(3-4):329-332
67.
This paper studies the timing of privatization in 21 major developed economies in the 1977–2002 period. Duration analysis shows that political fragmentation plays a significant role in explaining government’s decision to privatize: privatization is delayed longer in democracies characterized by a larger number of parties and operating under proportional electoral rules, as predicted by war of attrition models of economic reform. Results are robust to various assumptions on the underlying statistical model and to controlling for other economic and political factors. 相似文献
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69.
Susanne D. Mueller 《Journal of contemporary African studies : JCAS》2011,29(1):99-117
This paper examines the lessons learned from Kenya's 2007 post election violence and what has happened since then. It notes that the root causes of the violence still persist, have not been addressed, and easily could be reignited. Faced with a situation where institutions and the rule of law have been weakened deliberately and where diffused violence is widespread, both Kenya's transition to democracy and the fate of the nation remain vulnerable. The argument here is that the problems faced in holding and managing elections in conflict situations often are not simply technical. Instead, in Kenya and elsewhere, many difficulties are symptomatic of larger political and institutional questions related to democratic change that are more difficult to analyze in causal terms or to address. 相似文献
70.
In some Latin American nations, policy change occurs frequently, while in others it is stable, less prone to shifts with the prevailing political climate or shocks. The conditions under which institutional rules and the powers of key actors influence the capacity for governance vary, and this variation is seldom addressed in the literature. This project examines the effects of the interactions between key policymakers (the executive and the legislature) in Latin America on policy stability across different institutional frameworks. Countries with simultaneously strong executives and weak legislatures are shown to have unstable policy environments, as are countries with a history of unified government and, to a lesser extent, candidate‐centered electoral systems. 相似文献