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61.
62.
    
The effect of different supplementary feeding rates for grazing cattle on high-altitude pastures dynamics was evaluated. A field experiment was carried out during three years in a subalpine pasture area of the Eastern Alps. The investigated pasture area was 40?ha, located between 1820 and 2230?m?a.s.l. Two paddocks were chosen in the experiment and two herds of 12 cattle each were kept in the two enclosures for 5 weeks. For the first herd (HS), the supplementary feeding rate was 4.8?kg?OM?head?1 per day, while for the second herd (LS), the rate was 1.6?kg?OM?head?1 per day. The amount of herbage consumed by each cattle was determined using the n-alkane technique. To monitor the pasture vegetation dynamics, eight metal exclusion cages were placed in each paddock to determine herbage growth, utilization rates, vegetation composition and animal grazing selectivity. Grazing behaviour of dairy cattle, in terms of herbage intake and species selection was affected by the different feeding rates. Cattle grazing Paddock HS consumed 1.9?kg?OM?day?1 of herbage less than Paddock LS. In the LS paddock, cattle grazed higher phytomass rates. When the animals were fed by higher concentrate rates, a more selective grazing seemed to significantly increase the pasture necromass component. The lower grazing selectivity favoured the development of species as Nardus stricta and Deschampsia caespitosa, which are well known for their low palatability. Distinct vegetation dynamic patterns were observed, with a reduction of hair grass and an increase of legumes in the Paddock LS.  相似文献   
63.
The nexus between trade and economic growth in Italy has been widely debated by historiography. However, there are no long run analyses on this topic that cover the whole span from Unification to present days. This paper contributes to fill this gap by investigating the relationship between real exports, imports and GDP in Italy from 1863 to 2004 by using cointegration analysis and causality tests. The outcome suggests that these variables comove in the long run but the direction of causality varies across time. In the period prior to the First World War import growth led GDP growth that in turn led export growth. Conversely, in the post-Second World War period we have a strong bidirectionality between imports and exports consequent on the increase in intra-industry trade. We also find a weak support for export-led growth and growth-led imports. This suggests that exports were not the only or the main driver of economic growth. There was probably a multiplicity of factors at work, among which high rates of capital formation and the expansion of internal demand probably stood out.  相似文献   
64.
    
Over the last several years—in the context of US political upheaval, ongoing crises related to climate change, the COVID-19 pandemic and an economic downturn—indigenous, Mexican-origin farmworker families in Washington State have engaged more intensely in class struggle through acts of solidarity and forms of collective action, in part through independent labour unions, worker cooperatives and mutual aid. This article chronicles the labour struggles that led to a notion of class rooted in family units of production and that strengthened transnational solidarity in resistance to racist forms of exploitation in the agricultural sector. Class organization rooted in family and solidarity has allowed indigenous agricultural workers in Washington State to face COVID-19 and incidents driven by climate change, which syndemically compounded existing community health crises, from a place of power. Focusing on the experience of farmworker families in Washington State, I outline agricultural employers' exploitation of workers during this period of increased vulnerability and the strength of farmworkers' resolve to take their health and well-being into their own hands.  相似文献   
65.
The paper analyzes the impact of e-business technologies on maintenance management and supply chain operations. The aim of this work is to investigate the network organization level of supply chains in case of remote maintenance application and to understand how maintenance policies are coupled with information technology (IT) solutions. To this purpose two literature reviews are presented: firstly, on the supply chain and network integration, and then on the evolution of maintenance using information technology. Following this, the paper present four specific industrial case-studies of eMRO network organisation. They have been chosen as reference models from a set of practical applications and pilot tests performed by the authors in different production sectors in the last 5 years. Technology complexity environments, maintenance outsourcing level, and supply chain integration context are discussed for each case-studies with particular regards to the profitable forms of collaboration provided by the introduction of IT and the Web. This analysis work toward the development of a framework useful to: (1) classify different e-maintenance systems and understand the relationships between the different members of the network, and (2) identify the variables which can influence the introduction and development of the systems.  相似文献   
66.
The strategic analysis of the private provision of a discrete public good has shown the existence of multiple Nash equilibria with the efficient number of players voluntarily contributing. However the coordination issue is left unexplained by this literature. The experimental evidence shows that communication among players is helpful in achieving cooperation. We claim that, from the theoretical point of view, this is equivalent to playing correlated equilibria in an extended public good game with communication, modeled as Chicken. We characterize such equilibria as feasible coordination mechanisms to achieve public goods provision in the general contribution game. We further introduce a second kind of game characterized by payoff externalities that may persist after the minimal threshold of contributors is achieved. While it is easy to show the existence of Pareto efficient correlated equilibria in the first game, in the second one players face incentive problems such that a first best cannot always be an equilibrium. Nevertheless there exist correlated equilibria that can qualify as incentive efficient mechanisms, once free riding is seen as a moral hazard issue. Finally, with an example, we discuss the impact of coalition formation in our framework.  相似文献   
67.
    
This article examines the responsiveness of real output to the variability of inflation and aggregate demand. In the manner of Lucas (1973), estimates of the output-inflation tradeoff are computed for a large sample of countries. This measure is then correlated with the variances of the inflation rate and the growth rate in nominal income. Because differences in inflation variance (and hence the tradeoff) are viewed as the outcomes of differences in demand variance, correlations between these two variables are also reported. Cross-time and cross-country results provide a good measure of support for Lucas and the notion that attempts to exploit the tradeoff weaken it.  相似文献   
68.
    
In this paper we present a structuralist two‐sector model on economic development, structural change and natural resource booms. We describe a multiple equilibria scenario, in which manufacturing development is the main source of economic progress. Natural resource booms, by modifying the productive structure of the economy, may set destabilizing forces. De‐industrialization processes may take place, confining developing countries in poverty traps. Public intervention in the economic sphere, both through short‐run macro policies and through long‐run development strategies, may help to free the economy from poverty traps and to foster the development process.  相似文献   
69.
    
This paper is aimed at contributing to the literature on income and wealth inequality by proposing a simple stochastic model in which wealth accumulation depends on the ‘social relation’ between two classes: capitalists or workers. As a result, the society may evolve towards an unequal outcome with few rich and many poor individuals. We study the dynamic properties of the model by means of computer simulations. A maximum likelihood estimation procedure is applied to analyse the Pareto or power law tail of wealth distribution. We also provide a scenario analysis to explore the system's behaviour under alternative parameter settings.  相似文献   
70.
To assess significant changes of health status in people receiving health care, distribution-based and anchor-based methods have been proposed. However, there is no real consensus on what method is the best for evaluating clinically meaningful change. To maximize the internal and external validity of outcome assessment, we propose combining two approaches as recommended by recent practical guidelines on this field. Specifically, we suggest applying longitudinal hierarchical linear models on subgroups of patients showing reliable change and reliable and clinically significant change. This combined approach improved the model’s ability (1) to quantify the magnitude of changes to be reliable and clinically meaningful and (2) to select significant predictors of changes. An empirical application on a prevalence sample of Italian outpatients attending four community mental health services was done. A cross-sectional model and three longitudinal models were applied on the entire study sample and reliable and clinically meaningful change subsamples to investigate the magnitude of change and the predictive effect on outcomes of clinical, socio-demographic and process variables on different patients’ subgroups. Differences were found suggesting that both the statistical method and the sample used to calculate individual changes affect the estimates. The main conclusion is that ignoring the longitudinal data structure or including patients with unreliable change at the follow-up might result in misleading inferences that can alter the real magnitude of changes and the contributions of predictors. The approach proposed provides robust feedback to clinicians on clinically significant change and can be recommended in outcome studies and research.  相似文献   
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