全文获取类型
收费全文 | 2792篇 |
免费 | 120篇 |
国内免费 | 49篇 |
专业分类
财政金融 | 94篇 |
工业经济 | 103篇 |
计划管理 | 450篇 |
经济学 | 720篇 |
综合类 | 301篇 |
运输经济 | 14篇 |
旅游经济 | 44篇 |
贸易经济 | 186篇 |
农业经济 | 643篇 |
经济概况 | 406篇 |
出版年
2024年 | 11篇 |
2023年 | 58篇 |
2022年 | 108篇 |
2021年 | 100篇 |
2020年 | 131篇 |
2019年 | 55篇 |
2018年 | 52篇 |
2017年 | 70篇 |
2016年 | 97篇 |
2015年 | 88篇 |
2014年 | 150篇 |
2013年 | 130篇 |
2012年 | 240篇 |
2011年 | 298篇 |
2010年 | 207篇 |
2009年 | 212篇 |
2008年 | 199篇 |
2007年 | 184篇 |
2006年 | 176篇 |
2005年 | 98篇 |
2004年 | 72篇 |
2003年 | 51篇 |
2002年 | 43篇 |
2001年 | 40篇 |
2000年 | 29篇 |
1999年 | 15篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1990年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有2961条查询结果,搜索用时 15 毫秒
71.
Land and water resource issues typically fall under separate governance systems. For example, agricultural policy regulates land-cover change while water departments regulate water quality. However, land-use changes can directly affect water resources. Water flow regulation is a key service which is affected by changes in land-cover but its dynamics are poorly understood by most policy makers and land management organisations. We simulated and quantified the effects of plant invasions on land-cover, hydrological soil characteristics and catchment responsiveness on flow regulation using a hydrological model. The case study was located in the indigenous fynbos shrublands in South Africa. Fynbos requires fire to regenerate, has moderate biomass, occurs mostly in areas with a potential to erode and is prone to invasion by woody plant species, particularly trees. Invasions can affect flow regulation by changing community structure and function and increasing fuel loads. The greater fuel load increases fire intensity and severity which, in turn, changes the hydrological responses of catchments. Few studies have assessed the effects of invasion on hydrological responses but studies on plantations have recorded significant increases in soil water repellence following fire, resulting in increased overland flow similar to impacts of fires in invaded areas. Simulation of clear-felling of pines and different degrees of water repellency increased both the responsiveness of the catchment to rainfall and extreme rainfall events. The simulated fire effects were consistent with other studies of hydrological responses to fire. Our study indicates that invasions of pines and acacias in the study area could substantially increase the risk of flood damage even from moderate rainfall events, and highlights the importance of maintaining flow regulation capacity. New policy approaches are required which take account of the linkages and interactions between land-use choices, water resources and ecosystem services, and address them when considering governance arrangements. 相似文献
72.
73.
This paper evaluates the existing policy frameworks for mitigation of diffuse water pollution from agriculture (DWPA) in England and China. With reference to a conceptual model of the process of policy transfer or international lesson drawing, and possible constraints to this, it assesses whether and how China can draw lessons to improve current policy from the supra-national and national provisions of the EU and a member state that by 2016 had comprehensively implemented EU agricultural and environmental policy. DWPA is first analysed as a public policy challenge to inform specification of a generic framework for its mitigation. The current policy frameworks for mitigation of DWPA in England and China are evaluated, and their potential for improvement is assessed. A number of barriers to lesson drawing for regulation, incentive payments schemes and advice provision are diagnosed. These barriers are potentially least in relation to advice provision and its use to promote voluntary action by farmers. Given its structure and capabilities the public agricultural extension system in China is also recognised as a key resource. A focus on three policy approaches to mitigate DWPA in China is recommended: i) targeted regulation to a ‘reference level’ of large intensive livestock, and ultimately other large commercial farms; ii) strategic use of incentive payment schemes to protect water resources from DWPA; and iii) re-orientation of the ethos and modalities of operation of the extension system, informed by international lesson drawing, with the aim of rebalancing farm productivity and environmental protection. 相似文献
74.
Irrigation water productivity in Cambodian rice systems 总被引:1,自引:0,他引:1
Knowledge of the marginal productivity of water is crucial for decisions about its allocation between uses, which is particularly important in the context of increasing competition for water. Using primary, plot‐level panel data, this article estimates the marginal productivity of water from supplementary irrigation in lowland rice systems in Cambodia, taking into account farmer and plot heterogeneity as well as self‐selection of supplementary irrigation. Our estimates indicate a range of elasticities for rice output with respect to water inputs of between 0.057 and 0.069 for wet season production, substantially lower than previous estimates based on either aggregate or trial data. We discuss the policy implications of these results, in particular with respect to the utility of demand management policies and the challenges they pose to the decentralization of water management to Farmer Water Users Groups. 相似文献
75.
珠江三角洲的产业集群表现为专业镇的形态,其治理主体为当地镇政府。面对不断增长的挑战。需要培育和发展新的治理主体,这包括核心大企业和行业协会.根据分工网络的特征和产业集群的成因,珠江三角洲的产业集群可以分为四种类型,它们有不同的核心企业,也有不同的升级路径。行业协会在推进行业协调与治理及为企业提供多方面服务方面可以发挥重要作用,行业协会功能的发挥仍需一个培育过程。 相似文献
76.
《Accounting Forum》2017,41(3):161-171
The case for the greater use of narrative disclosures within the annual report package continues to attract support from accounting academics. After a decade of comparatively limited attention, the topic of narrative reporting has returned to the accounting research agenda, in part in association with integrated reporting and a growing interest in accounting for business models, as well as a resurgence of intellectual capital research. In the light of a continuing optimism that narrative reporting will eventually assume its rightful place within financial reporting, the paper reports and reflects upon the findings of a study of the outcome of the Danish Guideline Project in the decade following its conclusion in late 2002. This initiative placed a heavy emphasis on the extension of narrative reporting in its principal output, the Intellectual Capital Statement, still widely regarded as a highly promising intellectual capital reporting framework. Based on insights derived from the study, the paper identifies a number of major obstacles that confront the advocates of narrative disclosure practices, the persistence of which is rooted in the contestable jurisdiction that characterises the accountancy profession itself. 相似文献
77.
The water industry is in great need of further large investments to address existing severe water shortages worldwide which requires the participation of private sector investors. This industry is heavily infrastructure based and is therefore saddled with fixed assets-in-place or illiquid assets. This exposes the industry to what is termed as ‘illiquidity risk’, and hence, investors in this industry should be compensated for bearing this risk with an appropriate return premium (i.e. extra return). In this study, we provide evidence as to whether illiquidity risk indeed significantly affects returns in this industry. We examine the case of all 76 firms that compose the five major global water indices. After controlling for other factors that impact on returns, our results suggest that asset illiquidity is positively associated with stock returns. Specifically, water firms with a larger proportion of illiquid assets-in-place are observed to have greater stock returns than those with a smaller proportion of illiquid assets. Our results have important implications for the financing of water-related projects particularly those which involve the participation of investors from the private sector. 相似文献
79.
The paper discusses the relevance of a stronger articulation between land use and water resources systems to enhance the success of the Water Framework Directive. Using article 11 of the WFD, this paper assess (i) how the Spatial Planning and Urban Development Law as well as the Portuguese Water Law converge to promote better integration of water resources into spatial planning, (ii) how their prospects are developed at the regional basis, namely through the Regional Spatial Development Plan and River Basin Management Plan, and (iii) how these are prepared to inform other planning instruments at the local level. It shows through a spatial analysis of the regional land-use plan and the river basin plan as applied over the Ria de Aveiro estuary area, the conflicts and opportunities for stronger synergies. The paper concludes with a critical analysis of the integration of the spatial planning and water resources planning systems in Portugal, and reveals new insights and challenges for more productive synergies between these systems. 相似文献
80.
长江三角洲地区是我国经济发展的先导区域,其发展成功与否决定着能否实现中华民族的复兴。本文通过对欧洲莱茵河流域和长江三角洲地区经济发展的对比分析,提出了若干长江三角洲经济区的发展战略。 相似文献