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151.
The kappa statistic is suggested as a means to index the degree to which particular patterns occur in social interaction. It is suggested that the value of the kappa statistic for each interaction be used as a dependent measure. Particular formulas for kappa are derived for undirectional dependence, bidirectional dependence, other additive patterns, and for dominance.  相似文献   
152.
Food security for the world in 2025 is possible and probable if the right set of things are done, starting now. But the task will not be easy. It is both a technology and a political/economic challenge. The challenge for sub-Saharan Africa is even greater. While other regions improved per capita food availability over the last 30 years, Africa's availability declined. But food security is about more than supply. It is also about access which means income generating employment is critical. Meeting future requirements in Africa and the world will require sustainable intensification of complex production systems, appropriate national and international policies and continued investments in agricultural research. Without these conditions and increased employment intensive growth, prospects for the future are less bright.  相似文献   
153.
Most studies of alcohol-related traffic fatalities find beer taxes to be an important policy variable. This is surprising since beer taxes only have a small impact on consumption and heavy drinkers are the least responsive to prices. This study shows that the tax relationship is not robust across data periods and that it reflects missing variable biases. While lack of control for law enforcement effort does not appear to bias tax coefficients, failure to include determinants of alcohol consumption other than taxes and drinking age and/or factors that simultaneously determine drinking behavior and political support for alcohol taxes apparently do.  相似文献   
154.
Drawing on research in management theory, risk analysis, and the social sciences, this installment of Business Law & Ethics Corner promotes diversity of thought in corporate governance as not only beneficial to business growth and creativity, but also imperative to managing risk successfully. The article begins with a review of four major worldviews and the risk preferences of each. Next, it examines psychological processes that guide human decision making and greatly influence risk perception. The article then applies these worldviews and psychological phenomena to the case of risk management. It offers a critique of current risk management practices, drawing on evidence from the 2007–2008 financial crisis. The article concludes by promoting increased diversity of worldviews in corporate governance as a way to prevent the same risk blindness that led to the Great Recession.  相似文献   
155.
The role of international and internal migration in facilitating or inhibiting development is currently attracting considerable attention globally. In southern Africa, the migration–development nexus has been researched for a number of years and policy makers in both the development and migration fields are now paying it increasing attention and increasingly recognising the significance of migration for development and poverty reduction. Much of the international debate on this nexus is hampered by the absence of sound, reliable national and local data. This collection of essays by southern African researchers combines the national with the local, the quantitative with the qualitative, and addresses several prominent themes in the global migration–development debate: remittances, the brain drain and migrant rights. It also focuses on key migration–development issues which have received less attention globally, but which are of critical importance to southern Africa: migration and HIV/AIDS, migration and food security and the rural impact of migrant retrenchments. This Introduction to the collection contextualises the essays within current international and local debates.  相似文献   
156.
157.
Some stocks have meaningful ticker symbols; for example, LUV (Southwest Airlines), MOO (United Stockyards), and GEEK (Internet America). Such tickers might be a useful signal of the company's creativity, a memorable marker that appeals to investors, or a warning that the company feels it must resort to gimmicks to attract investors. This paper investigates the performance of stocks with memorable ticker symbols during the years 1984–2005 and finds that, on average, their daily returns are higher than for the overall market.  相似文献   
158.
This study is the first to examine the intraday behavior of quoted depth in a competitive dealer market. In sharp contrast to previous research that focuses on specialist markets, quoted depth is lowest at the open of trading, plateaus around the middle of the day, and then dramatically increases in the final hours of trading, peaking at the close. This peak in quoted depth coincides with a narrowing in bid‐ask spreads, and is contrary to intraday patterns documented for specialist markets. The authors conclude that the increase in depth and narrowing of bid‐ask spreads at the close is driven by dealers rebalancing inventories to achieve target inventory levels in a competitive market. © 2008 Wiley Periodicals, Inc. Jrl Fut Mark 28:294–307, 2008  相似文献   
159.
Federal lab commercialization is explored: (1) by analyzing US government patents and (2) in a qualitative analysis of one NASA lab's patents. Tests apply to three distinct sets of patents, 1963–94: NASA, all other US government, and a random sample of all US inventors' patents. The federal patenting rate plummeted in the 1970s. Consistent with increasing commercialization, both NASA's and other federal agencies' rates recovered in the 1980s. The case study finds citations to be a valid but noisy measure of technology spillovers. Excluding 'spurious' cites, two-thirds of cites to patents of NASA-Lewis' Electro-Physics Branch were evaluated as involving spillovers.  相似文献   
160.
Logistics management in grain marketing has become very important with the maturity of the industry. This is particularly critical in the Canadian grain marketing system, which has experienced disruptions for various reasons over many years. These problems have been the topic of numerous industry evaluations, have resulted in a complaint about service obligations during the 1996–97 crop year, and were addressed by the Estey Commission. A detailed model of the Canadian grain logistics system is developed in this paper to evaluate factors that cause disruptions, as well as the effect of several important logistics and marketing strategies on system performance. The results illustrate that there is sufficient randomness throughout the various functions of the system that it is expected that demurrage at the west coast would periodically be an important cost. The frequency of service disruptions and demurrage are affected by several factors, including the distribution of tough and damp grains, mis‐graded grain and the level of exportable supplies. Several strategic variables affect system performance. These include the aggressiveness in selling relative to capacity and the level of beginning port stocks. La gestion de la logistique dans le commerce des céréales a acquis une grande importance maintenant que ce secteur a atteint la maturité. C'est particulièrement important dans le système canadien de mise en marché des céréales lequel, pour diverses raisons, a essuyé bien des perturbations ces dernières années. Les problèmes en cause ont fait l'objet de nombreuses évaluations du secteur. Ils ont même abouti au dépôt d'une plainte sur les obligations de service dans la campagne agricole 1996–1997 et ont étéétudiés par la Commission Estey. Dans la présente communication nous avons construit un modèle détaillé du système canadien de logistique du marché des céréales ainsi que de l'effet de plusieurs stratégies importantes de logistique et de commercialisation sur la performance du systeme. Les résultats obtenus montrent qu'il y a suffisamment d'aléatoire dans les diverses fonctions du systeme pour conclure que les frais de séjour à quai sur la côte ouest seraient périodiquement un important poste de dépense. La fréquence des perturbations des services et les coûts a quai sont associés à plusieurs facteurs dont la livraison de grain gourd et humide, de grain mal classé et le niveau des disponibilités exportables. Plusieurs variables stratégiques influent sur le fonctionnement du système, notamment l'agressivité manifestée dans la vente par rapport aux stocks disponibles et le niveau des stocks disponibles dans les ports au début de la campagne d'exportation.  相似文献   
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