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181.
This paper studies production planning of manufacturing systems of unreliable machines in tandem. The manufacturing system considered here produces one type of product. The demand is assumed to be a Poisson process and the processing time for one unit of product in each machine is exponentially distributed. A broken machine is subject to a sequence of repairing processes. The up time and the repairing time in each phase are assumed to be exponentially distributed. We study the manufacturing system by considering each machine as an individual system with stochastic supply and demand. The Markov Modulated Poisson Process (MMPP) is applied to model the process of supply. Numerical examples are given to demonstrate the accuracy of the proposed method. We employ (s, S) policy as production control. Fast algorithms are presented to solve the average running costs of the machine system for a given (s, S) policy and hence the approximated optimal (s, S) policy. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 65–78, 2001  相似文献   
182.
    
We study an (R, s, S) inventory control policy with stochastic demand, lost sales, zero lead‐time and a target service level to be satisfied. The system is modeled as a discrete time Markov chain for which we present a novel approach to derive exact closed‐form solutions for the limiting distribution of the on‐hand inventory level at the end of a review period, given the reorder level (s) and order‐up‐to level (S). We then establish a relationship between the limiting distributions for adjacent values of the reorder point that is used in an efficient recursive algorithm to determine the optimal parameter values of the (R, s, S) replenishment policy. The algorithm is easy to implement and entails less effort than solving the steady‐state equations for the corresponding Markov model. Point‐of‐use hospital inventory systems share the essential characteristics of the inventory system we model, and a case study using real data from such a system shows that with our approach, optimal policies with significant savings in inventory management effort are easily obtained for a large family of items.  相似文献   
183.
    
ABSTRACT

This article examines Chinese views of North Korea’s nuclear-weapon program during the Donald J. Trump administration. It shows that China has portrayed itself as a responsible country that promotes regional stability, unlike the United States, which has engaged in military brinkmanship with North Korea. Some Chinese foreign-policy experts have asserted that Beijing should back Pyongyang in the event of war because of their shared history of humiliation by great powers, while others have favored working with other regional partners. Another theme in Chinese discourse about North Korea is that Pyongyang is an impetuous, ungrateful regime that impedes Beijing’s ability to attain its core interests of regional stability, economic development, and heightened global influence. This negative assessment of North Korea drove Beijing’s endorsement of stricter UN sanctions in 2017. While Beijing has punished Pyongyang for its wayward policies, China responded favorably to North Korea’s decision in April 2018 to stop nuclear tests and partake in international dialogue. Beijing seeks to help Pyongyang gradually disarm and develop its economy within a Chinese-led East Asian order. The article concludes by explaining how Beijing’s recent, more positive view of Pyongyang is likely to affect its support for American efforts to dismantle North Korea’s nuclear-weapon program.  相似文献   
184.
    
The end of the 1987 Intermediate-range Nuclear Forces (INF) Treaty has the potential to plunge Europe and NATO into deep crisis. Russia’s continued violation coupled with the Donald J. Trump administration’s desire to balance against Moscow and Beijing could force a new missile debate on Europeans. Even though Washington is trying to assuage its allies, the specter of another round of INF missile deployments to Europe is not unrealistic. Meanwhile, NATO’s European members face a dilemma. Some want NATO to resolutely push back against Russia. Others want to avoid a new deployment debate, at almost all costs. The Kremlin will use these cleavages to weaken NATO. If not carefully handled, NATO’s response to the Russian missile buildup could lead to domestic turmoil in a number of European states and render the alliance ineffective for a prolonged period. Europeans need to act now and voice their preferences in the military and diplomatic domains. A number of different military options are available, below the level of deploying new INF missiles in Europe. However, Europeans need to consider trade-offs regarding crisis and arms-race stability. At the same time, it will be up to European capitals to conceptualize a new arms-control framework for the post-INF world, one that takes into account today’s geopolitical realities and the entanglement of modern conventional and nuclear forces. Given the Trump administration’s loathing of arms control, concepts of mutual restraint may well have to wait for the next US administration. In any case, that should not stop Europeans from taking on more responsibility for their own security.  相似文献   
185.
    
ABSTRACT

As the United States and North Korea pursue negotiations on a “denuclearization” agreement, the two countries should consider initiating cooperative measures as a way to build confidence and encourage finalization of a complete agreement. Based on lessons from the initial engagements carried out under the Cooperative Threat Reduction (CTR) program in states of the former Soviet Union (FSU), initial cooperation should focus on safety and security, training, and infrastructure elimination. By offering to implement these initiatives now while negotiations are underway, the United States could gain additional insights into North Korean intentions. These early initiatives could be proposed without compromising the US maximum-pressure campaign on North Korea by using the current authorities of the CTR program and carefully designing specific exemptions that may be required for any agreed measures. If North Korea is truly interested in pursuing disarmament efforts, the initial cooperative projects would enable them to begin reaping potential benefits while negotiations continue with sanctions still in place. These initial proposals could also be expanded to include additional international partners such as Russia, China, South Korea, and Japan. Such programs and initiatives would support and supplement longer-term strategies to address North Korean weapons-of-mass-destruction challenges.  相似文献   
186.
    
This study revisits the relationship between defence spending and economic growth via a Keynesian model in Pakistan using the autoregressive distributive lag bounds testing approach to cointegration. Empirical evidence suggests a stable cointegration relationship between defence spending and economic growth. An increase in defence spending reduces the pace of economic growth confirming the validity of Keynesian hypothesis in this case. Current economic growth is positively linked with economic growth of previous periods while a rise in non-military expenditures boosts economic growth. Interest rate is inversely associated with economic growth. Finally, unidirectional causality running from military spending to economic growth is found.  相似文献   
187.
    

European defence policy has been dominated by politics. This paper shows how economic principles can be used to derive guidelines for the formulation of European defence policy. The inefficiencies of the EU's existing defence arrangements are identified. It is shown that there is scope for efficiency improvements in the EU's Armed Forces and its defence industries.  相似文献   
188.
This paper investigates a series of unit root, cointegration and causality tests to ascertain the direction of causality between the growth of GNP and defence expenditure in Turkey for the years 1955–2000. The main conclusion is that there is a long‐run equilibrium relationship between GNP and defence expenditures. Furthermore, the short run causality test indicates that there is a unidirectional causality between variables, from defence expenditure to economic growth. In order to see the effect of a shock, we employed impulse response analyses. The results show that GNP decreased during the period then output finally recovered from the initial shock to defence expenditures.  相似文献   
189.
    
Uruguay is a country with a very unusual profile, since it has just 3.4 million inhabitants but is among the top ten troop contributors to the UN PKO (Peace Keeping Operations) and is the first contributor per capita. In 2002 and 2003 it was the seventh troop contributor to the UN, and by the end of 2005 it was eighth in the UN ranking. Uruguay has never had any imminent external threat to its security after its independence in 1828, and it has had no internal threat since the end of the urban guerrillas’ actions in the 1970s. The country has no defence industry, and has always had an all‐volunteer military service, which presently involves almost 1% of the total population, and about 2% of the labour force. The empirical evidence presented in this paper shows that, in the past decades, Uruguayan defence spending has been influenced mainly by internal factors, most of them of an economic nature. The high participation in PKO has not increased military expenditure and it has produced a positive impact on the country’s economy.  相似文献   
190.
    
This paper empirically re‐examines the long‐run co‐movements and the causal relationships between GDP and defence expenditures in a multivariate model with real defence expenditure per capita (ME), real GDP per capita (GDP), and real capital stock per capita (K). We apply the view of the aggregate production function to construct the empirical model. Using up‐to‐date data for 27 OECD countries and 62 non‐OECD countries for the 1988–2003 period, we combine cross‐sectional and time series data to re‐investigate the relationship between GDP and ME. Previous studies using time series data may have yielded misleading results on account of the short time span of typical datasets. By contrast, we use recently developed panel unit root tests and heterogeneous panel cointegration tests, and conclude that there is fairly strong evidence in favour of the hypothesis of a long‐run equilibrium relationship between GDP and ME. The long‐run panel regression parameter results, such as the fully modified OLS, indicate that a positive relationship between GDP and ME only holds for OECD countries, whereas a negative relationship from ME to GDP only exists in non‐OECD countries under examination and in the panel as a whole. Furthermore, by implementing the dynamic panel‐based error correction model, we determine that GDP and ME lack short‐run causalities, but do show long‐run bidirectional causalities in both OECD and non‐OECD countries.  相似文献   
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