首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3930篇
  免费   77篇
  国内免费   8篇
财政金融   714篇
工业经济   113篇
计划管理   788篇
经济学   944篇
综合类   416篇
运输经济   40篇
旅游经济   105篇
贸易经济   490篇
农业经济   59篇
经济概况   346篇
  2024年   2篇
  2023年   56篇
  2022年   108篇
  2021年   146篇
  2020年   166篇
  2019年   107篇
  2018年   103篇
  2017年   146篇
  2016年   132篇
  2015年   93篇
  2014年   188篇
  2013年   315篇
  2012年   258篇
  2011年   304篇
  2010年   232篇
  2009年   253篇
  2008年   282篇
  2007年   276篇
  2006年   243篇
  2005年   186篇
  2004年   113篇
  2003年   63篇
  2002年   58篇
  2001年   39篇
  2000年   20篇
  1999年   47篇
  1998年   4篇
  1997年   11篇
  1996年   6篇
  1995年   8篇
  1994年   4篇
  1993年   10篇
  1992年   7篇
  1991年   6篇
  1990年   8篇
  1989年   2篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1984年   4篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
排序方式: 共有4015条查询结果,搜索用时 15 毫秒
1.
Predicting consumption behavior is very important for adjusting supplier production plans and enterprise marketing activities. Conventional statistical methods are unable to accurately predict green consumption behavior because it is characterized by multivariate nonlinear interactions. The paper proposes an optimized fruit fly algorithm (FOA) and extreme learning machine (ELM) model for consumption behavior prediction. First, to address the problem of uneven search direction of FOA leading to insufficient search ability and low efficiency, the paper proposes a sector search mechanism instead of a random search mechanism to improve the global search ability and convergence speed of FOA. Second, to address the issue that the initial weights and hidden layer bias values of the ELM are randomly generated, which affects the learning efficiency and generalization of the ELM, the paper uses an improved FOA to optimize the weights and bias values of ELM for improving the prediction accuracy. Taking the green vegetable consumption behavior of Beijing residents as an example, the results show the optimization of the initial weight and threshold of ELM by the GA, PSO, FOA, and SFOA, the prediction accuracy of the GA-ELM, PSO-ELM, FOA-ELM, and SFOA-ELM models all surpass those of ELM. Compared with BPNN, GRNN, ELM, GA-ELM, PSO-ELM, and FOA-ELM models, the RMSE value of SFOA-ELM was decreased by 9.45%, 8.40%, 11.89%, 5.84%, 2.22%, and 2.69%, respectively. These findings demonstrate the effectiveness of the SFOA-ELM model in green consumption behavior prediction and provide new ideas for the accurate prediction of consumption behaviors of other green products with similar characteristics.  相似文献   
2.
Plastic pollution is a global environmental crisis that poses a huge threat to the health of people and marine ecosystems worldwide. A significant source of plastic pollution is menstrual hygiene management, and an approach that can help address this crisis is the usage of washable and reusable menstrual cups. Using an extended theory of planned behavior model that includes self-identity and perceived quality, the study predicted intentions to use menstrual cups in the Philippines. Structural equation modeling results showed that perceived quality predicted attitudes towards menstrual cup usage. Moreover, attitudes, perceived behavioral control, and self-identity predicted intentions to use menstrual cups. There were also some differences in the factors and predictors of intentions between non-users and regular users of menstrual cups. Among regular users, perceived behavioral control did not predict intentions. These findings provide empirical support for the extended model, and provides insights for governments, non-government organizations, and corporations in promoting the usage of menstrual cups to address the global plastic pollution crisis.  相似文献   
3.
乔智 《南方经济》2018,37(8):47-59
近年来针对股市资产价值变动与消费关系的研究多采用宏观数据,难以揭示股市资产价值变动对居民消费影响的细节。为克服以上缺陷,文章利用中国家庭金融调查(CHFS)数据分析股市资产价值变动对中国居民消费的影响。实证结果表明:(1)股市资产价值变动对居民消费的影响总体较弱,其中市值变动的财富效应主要体现在改善性消费上,而对饮食等日常必须消费和奢侈品消费影响较小,这可能与我国居民的收入结构和投资方式有关;(2)随着年龄增长,居民的收入分布和资产配置倾向发生改变,股市资产价值变动对不同年龄居民消费的影响呈现先减小后增大的U型分布。研究结论揭示了股市资产价值变动对居民消费影响的分布特征,为今后股市改革方向提供了建议。  相似文献   
4.
政府补贴能否促进企业创新一直存在争议。与以往从资源视角探讨政府补贴与企业创新关系的研究不同,基于信号理论视角,以2012—2016年沪深A股非金融类上市公司为研究样本,通过剔除非研发补贴的噪音并控制样本自选择偏误,实证检验中国转型经济背景下,政府研发补贴对企业创新的微观政策效应,以及企业层面制度因素(产权性质)和区域层面制度因素(制度环境)对该效应的调节作用。研究发现,政府研发补贴释放的积极信号能够帮助企业获取外部创新资源,有效促进企业创新;相比于国有企业,政府研发补贴对非国有企业创新的激励效应更强;制度环境越好,政府研发补贴对企业创新的激励效应越强。研究理论丰富了科技创新政策有效性和信号理论相关研究。同时,研究发现,政府应继续加大对企业创新活动的补贴额度,不断深化所有制改革,为企业创新营造良好的外部制度环境;另外,企业还应充分发挥政府研发补贴信号的杠杆效应,拓宽外部创新资源获取渠道。  相似文献   
5.
张翠芝 《现代食品》2020,2(4):176-178
超声波技术因其具备适应性强、操作简单、设备投资低等优势而被广泛应用于食品检测领域。本文介绍了超声波技术检测食品的原理和在食品检测中的应用价值,并详细阐述了该技术在食品检测中的具体应用,为超声波技术更好的应用于食品检测领域提供参考。  相似文献   
6.
韩炜  彭靖 《南方经济》2021,40(10):85-102
创业网络对具有新进入缺陷的新创企业以及创业者而言有着至关重要的作用,不仅表现为"知识源"作用,也表现为"印记源"作用。印记理论指出个体或组织在其容易受到影响的时期,外部环境的显著特征将对其产生重大影响,个体和组织将打上环境特征的烙印,并且这种烙印将持续影响个体和组织的行为。基于此,本研究基于印记理论,利用对一家创业企业的归纳式纵向单案例分析探讨创业网络不同的结构属性经由何种印记过程,继而影响创业者学习方式的选择。结果表明:当创业网络表现为封闭、半开放以及开放的不同网络结构时,经由不同结构属性导致的结构印记和认知印记过程差异,影响着创业者实验式学习、观察式学习以及协同式学习的不同选择。  相似文献   
7.
This study is the first attempt to examine the extreme risk spillovers between Malaysian crude palm oil (CPO) and foreign exchange currencies of the three largest CPO importers: India, the European Union and China throughout the global financial crisis. Using daily data of three currencies, CPO spot and futures from 2000 to 2018, our results show: First, before the crisis, the unexpected change in foreign exchange rates is the primary driver of risk spillover to the CPO market. Second, during the crisis, the extreme movement of CPO spot returns is dominant in the Malaysian exchange rates relative to the euro. Third, after the crisis, the spillover flows from the CPO market to the foreign exchange market. Overall, our findings show the importance of CPO pricing dynamics in mitigating foreign exchange risk over the crisis period. This paper contributes to the extant literature by recognizing the effect of risk spillover on the targeted foreign exchange rate for portfolio allocation.  相似文献   
8.
赵烨  高翅 《技术经济》2019,35(10):107
名山风景区“人与天调”的风景系统代表了中国独有的山岳文化现象和山水相融的总体特征。在风景自然和文化整体性视角下研究风景系统的形态、类型及其形成原因和规律,分析了风景资源评价和风景特质评价的互补性;构建了“相-制-理”的名山风景区风景特质理论及其实践框架。以武当山为例,探索“以脉绘景”的风景特质之相、“山川流峙”的风景特质之制以及“因脉而成”的风景特质之理。最后总结了风景特质理论作为形态学理论、作为图谱理论、作为地脉文脉认识论实践的整体性特点及其应用前景。  相似文献   
9.
This paper reviews the pitching template proposed by Faff ( 2015 ). The article highlights the usefulness of this template for researchers. It is observed that there is scope for adapting this tool, with a template suitable for qualitative researchers being proposed. In the light of the various methodological differences through different research paradigms, it is envisaged that this adaptation will assist in bridging the schism between qualitative and quantitative research. It is also hoped that the proposed enhanced template will encourage qualitative researchers to submit to mainstream accounting journals and quantitative researchers to comprehend the value of qualitative research.  相似文献   
10.
Nature-based experiences can contribute to individuals’ connection to nature and intentions toward sustainable environmental behaviours. Conservation psychology can use tourism as a platform to modify tourists’ intentions and behaviours regarding key marine threats such as single-use plastics. This study examined changes to pro-environmental intentions, particularly regarding plastic use, in 267 nature-based tourists from Australia and Tonga who completed a whale watching/swim experience. A theory of planned behaviour (TPB) framework was used incorporating moral norms and environmental identity, which have been previously implicated in explaining pro-environmental actions. This study found that including moral norms in the TPB model significantly increased the ability to predict pro-environmental intentions. Further, when controlling for the TPB and moral norm variables, environmental identity explained a further 15% of tourists’ pro-environmental intentions. The findings suggest the original TPB model may be less suitable within a marine conservation context. Collectively, positive nature-based experiences, environmental identity, and moral norms are important in understanding tourist’s intentions to engage in sustainable environmental behaviours.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号