全文获取类型
收费全文 | 2165篇 |
免费 | 124篇 |
国内免费 | 40篇 |
专业分类
财政金融 | 59篇 |
工业经济 | 144篇 |
计划管理 | 513篇 |
经济学 | 401篇 |
综合类 | 234篇 |
运输经济 | 78篇 |
旅游经济 | 68篇 |
贸易经济 | 269篇 |
农业经济 | 315篇 |
经济概况 | 248篇 |
出版年
2024年 | 8篇 |
2023年 | 40篇 |
2022年 | 42篇 |
2021年 | 68篇 |
2020年 | 111篇 |
2019年 | 75篇 |
2018年 | 58篇 |
2017年 | 93篇 |
2016年 | 87篇 |
2015年 | 79篇 |
2014年 | 171篇 |
2013年 | 204篇 |
2012年 | 185篇 |
2011年 | 193篇 |
2010年 | 155篇 |
2009年 | 137篇 |
2008年 | 135篇 |
2007年 | 111篇 |
2006年 | 101篇 |
2005年 | 84篇 |
2004年 | 46篇 |
2003年 | 46篇 |
2002年 | 23篇 |
2001年 | 26篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 12篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有2329条查询结果,搜索用时 546 毫秒
131.
根据生态足迹的概念和计算方法,对黑龙江省2005年生态足迹进行了计算和分析。结果表明,黑龙江省2005年人均生态足迹为2.525 hm2,而实际生态承载力为1.395 hm2,人均生态足迹赤字为1.297 hm2,表明黑龙江的发展处在一种不可持续的状态。 相似文献
132.
Boru Douthwaite J. Marina Apgar Anne-Maree Schwarz Simon Attwood Sonali Senaratna Sellamuttu Terry Clayton 《国际农业可持续发展杂志》2017,15(3):238-252
There have been repeated calls for a ‘new professionalism’ for carrying out agricultural research for development since the 1990s. At the centre of these calls is a recognition that for agricultural research to support the capacities required to face global patterns of change and their implications on rural livelihoods, requires a more systemic, learning focused and reflexive practice that bridges epistemologies and methodologies. In this paper, we share learning from efforts to mainstream such an approach through a large, multi-partner CGIAR research program working in aquatic agricultural systems. We reflect on four years of implementing research in development (RinD), the program’s approach to the new professionalism. We highlight successes and challenges and describe the key characteristics that define the approach. We conclude it is possible to build a program on a broader approach that embraces multidisciplinarity and engages with stakeholders in social-ecological systems. Our experience also suggests caution is required to ensure there is the time, space and appropriate evaluation methodologies in place to appreciate outcomes different to those to which conventional agricultural research aspires. 相似文献
133.
由于节段间接缝的影响,导致预制节段预应力混凝土箱梁接缝处抗剪机理与连续整跨梁存在较大差异,在计算抗剪承载力时无法直接应用整跨梁抗剪计算公式。首先对节段拼装箱梁接缝处的抗剪机理进行分析,得到影响计算抗剪承载力的关键参数;其次在已有计算公式的基础上,考虑混凝土立方体抗压强度和接缝处键齿数等参数的影响,提出适用于这种抗剪承载力的计算公式;最后将提出的计算公式与试验数据对比,表明该计算公式中的参数物理意义明确,计算精度较高,为预制节段拼装预应力混凝土箱梁结构的设计及应用提供了一定理论基础。 相似文献
134.
Social Capital,Income Diversification and Climate Change Adaptation: Panel Data Evidence from Rural Ethiopia
下载免费PDF全文
![点击此处可从《Journal of Agricultural Economics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
David Wuepper Habtamu Yesigat Ayenew Johannes Sauer 《Journal of Agricultural Economics》2018,69(2):458-475
The choice between specialisation and diversification of income is driven by multiple, interacting factors, such as economies of scale and scope, risk considerations, context, and household characteristics. Using panel data from Ethiopia, we investigate the role of social capital and the covariate risk of climate change and their interaction. We find that households with greater social capital tend to be more specialised, implying that diversification and informal insurance are substitutes in the mitigation of risk. We also find that this effect is significantly weaker in regions more prone to climate change, which is consistent with the average farmer being aware that informal insurance is not an effective protection against risks that affect the entire social network. We use instrumental variable random effects estimation to account for the plausible endogeneity of social capital and we also establish that our results do not depend on the poorest and most constrained individuals in our sample. 相似文献
135.
Farmers in the Vietnamese Mekong Delta face a wide range of climate-related and hydrological factors which threaten rice production. Smallholder farmers must adapt to climate change to sustain rice production as their central and most important livelihood activity. A sample was stratified across agro-ecological areas in the Delta affected by flooding, alluvial soils, acid sulphate soils, and saline water intrusion and by derived farmer typologies. A rural livelihoods approach was used in focus group discussions and in-depth interviews to identify and enumerate enabling and constraining adaptation factors. Smallholders experienced diverse natural hazards such as floods, abnormal rains, high temperatures, water scarcity, and salinity intrusion specific to the agro-ecological areas. Adaptation was constrained by labour shortages, water quality, topography, access to combine harvesters, transportation infrastructure, dryers and household savings. Adaptation was enabled by farming techniques and experience, cooperative groups, water quantity, access to information, and ability to purchase agro-chemicals through credit. Small farmers (< 1?ha) were more constrained than large farmers (> 1?ha) who had an expanded livelihood asset base. A range of policy implications are discussed, but adaptation is not just about technological fixes but requires overall improvements in a range of human, social and financial components. 相似文献
136.
为利用投影寻踪(PP)技术科学,客观评价区域水资源可持续发展能力,基于生态环境、水资源和经济社会因素选取20个指标构建区域水资源可持续发展能力评价指标体系。利用新型仿生群体智能算法——凉亭鸟优化(SBO)算法优化PP技术最佳投影方向,提出SBO-PP水资源可持续发展能力评价模型,并构建灰狼优化(GWO)算法-PP模型、人工蜂群(ABC)算法-PP模型、差分进化(DE)算法-PP模型、地理生物学优化(BBO)算法-PP模型、粒子群优化(PSO)算法-PP模型作对比,以云南省2006—2015年及2020年水资源可持续发展能力评价为例进行实例研究。结果表明:SBO算法优化PP技术获得的适应度值优于GWO、ABC、DE、BBO和PSO算法,具有较好的求解精度、稳健性能和极值寻优能力。SBO-PP模型对云南省2006—2007年水资源可持续发展能力评价为"较差",2008—2015年评价为"中等",2020年评价为"较强"。 相似文献
137.
Can radical political‐economic transformation be achieved by electoral regimes that have not thoroughly reconstructed the state? Contemporary Venezuela offers an optimal venue for examining this question. The Chavista movement did not replace the previous state: instead, its leaders attempted to reform existing state entities and establish new ones in pursuit of its transformation agenda. It has also used its oil wealth to support cooperatively‐oriented economic activity, without necessarily fundamentally altering the property structure. Thus, the social change‐oriented political economy exists alongside the traditional one. Focusing on agrarian transformation, we examine ethnographically how these factors have impacted the state's capacity to attain its goal of national food sovereignty. We find that the state's ability to accomplish this objective has been compromised by lack of agency‐level capacity, inter‐agency conflict and the persistence of the previously‐extant agrarian property structure. These dynamics have influenced the state to shift from its initial objective of food sovereignty to a policy of nationalist food security. 相似文献
138.
Mohammad M. Alazaizeh Jeffrey C. Hallo Sheila J. Backman William C. Norman Melissa A. Vogel 《Journal of Heritage Tourism》2016,11(4):364-381
To achieve sustainability in heritage tourism, tourists should be placed at the heart of the management and planning processes. Indicators and standards-based frameworks were developed in the field of outdoor recreation management to manage and measure crowding and other problematic issues in parks and related areas. Using normative theory and visual research methods, this article aims to examine crowding standards of tourists at Petra Archaeological Park, and compare these standards between the types of heritage tourists suggested by a model developed by Bob McKercher. Results showed that tourists’ acceptability levels go down with an increasing number of tourists, and tourists who are highly motivated to visit heritage sites (i.e. purposeful and sightseeing heritage tourists) had the most restrictive acceptable number of tourists at the park. The normative standards formulated in this article provided a guidance to manage crowding at Petra. 相似文献
139.
140.
MNCs are expected to operate in a sustainable fashion. Implementation of sustainability requires the ability to acknowledge external (sustainability-related) knowledge, and to apply it in intra-company activities such as purchasing. We focus on absorptive capacities as potential drivers of sustainability, and investigate the effect that a purchasing function’s capacity to absorb and process knowledge has on social and environmental sustainability practices, and subsequently on economic performance in purchasing. We compare MNCs and non-MNCs using a structural equation model of a large set of survey data from four European countries and find that only realized absorptive capacities impact sustainability practices in purchasing and this impact is smaller in MNCs than in other companies. We suggest that companies respond to the demand for sustainability by strengthening their implementation capabilities: the potential to acquire and transform knowledge within a purchasing function is less relevant, and what matters is its application. 相似文献