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   77862篇
  免费   1734篇
  国内免费   266篇
财政金融   9480篇
工业经济   5249篇
计划管理   16380篇
经济学   14127篇
综合类   7849篇
运输经济   592篇
旅游经济   564篇
贸易经济   8734篇
农业经济   4603篇
经济概况   12099篇
信息产业经济   9篇
邮电经济   176篇
  2024年   114篇
  2023年   573篇
  2022年   1338篇
  2021年   2075篇
  2020年   1905篇
  2019年   1126篇
  2018年   1018篇
  2017年   1764篇
  2016年   1394篇
  2015年   1874篇
  2014年   2758篇
  2013年   4125篇
  2012年   6188篇
  2011年   9276篇
  2010年   8492篇
  2009年   5498篇
  2008年   5947篇
  2007年   5510篇
  2006年   5987篇
  2005年   5364篇
  2004年   1571篇
  2003年   1422篇
  2002年   1274篇
  2001年   1248篇
  2000年   602篇
  1999年   390篇
  1998年   250篇
  1997年   165篇
  1996年   124篇
  1995年   64篇
  1994年   68篇
  1993年   70篇
  1992年   61篇
  1991年   50篇
  1990年   38篇
  1989年   29篇
  1988年   28篇
  1987年   14篇
  1986年   2篇
  1985年   4篇
  1984年   38篇
  1983年   6篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1976年   3篇
  1975年   1篇
  1970年   1篇
  1967年   1篇
  1900年   1篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
31.
深入分析我国“一带一路”沿线地区风险投资时空格局及影响因素,有助于促进创新创业与企业发展、提高区域科技创新水平。运用空间分析方法和空间计量模型,对2003-2018年我国“一带一路”沿线139个城市风险投资的时空分布特征及影响因素进行分析,结果表明:①沿线地区的风险投资发展具有不均衡性,呈现为沿海高、西部低的分异格局;②风险投资的全局自相关系数均为正,呈现出明显的空间集聚特征;③风险投资机构数、国家高新区数量、风险投资退出、政府引导基金发展、财政科技支出对区域风险投资具有显著促进作用,环境污染对风险投资有一定抑制作用。随着ESG投资理念逐渐获得认可,沿线地区可以通过提升绿色发展水平促进风险投资发展。  相似文献   
32.
基于嵌入性视角,分别引入知识转移、合作模式作为中介变量和调节变量,深入探究关系质量影响企业知识创造绩效的内在机理。利用277份来自全国多地的制造业及高新技术企业调查问卷,采用多元回归方法进行实证研究。结果表明:经济型和社会型关系质量均正向影响企业知识创造绩效;社会型关系质量通过元素知识和架构知识转移正向影响企业知识创造绩效。在契约治理模式下,经济型关系质量更倾向于通过元素知识转移正向影响企业知识创造绩效;在股权治理模式下,社会型关系质量更倾向于通过架构知识转移正向影响企业知识创造绩效。  相似文献   
33.
In the context of personal income tax (PIT) reform in China in 2018, this paper examines some of the major issues of concern regarding the reform and income distribution. Using the China Personal Income Tax Micro‐simulation model, the paper compares the differences between the 2011 and 2018 PIT systems, and finds that residents relying on different income sources may face a large degree of real tax rate change. Once the tax system is altered to PIT 2018, the coverage of PIT for wage earners will decrease from 46.9 to 23.4 percent, the income redistributive effect will drop from 1.95 to 1.22 percent and the PIT's role in fiscal revenue will also be negatively affected. Nevertheless, if individual income continues to grow, the share of PIT in fiscal revenue is expected to return to the 2018 level in 2022, but its income redistribution function is difficult to recover in the short term. The paper finds that the effect of PIT on income distribution depends on the tax structure. Gradual transition to an “entirely comprehensive” tax system when conditions are appropriate will achieve better income redistribution results at a lower average tax rate.  相似文献   
34.
This article studies how aid for trade (AfT) affects the quality of recipient countries’ exports. It shows that the quality effect is most discernible for AfT for assistance in trade policy: a 50% increase in the value of AfT received in this category is associated with a 0.5–1% increase in the quality of exports to the donor and other OECD countries. On average, the actual AfT received for assistance in trade policy leads to a 2% upgrade of the recipient country in the quality ladder of all developing countries. Around half of this quality effect is driven by the quality improvement of continued products in continued markets (intensive margin), and the other half by the quality upgrading of new products in continued markets and existing products in new markets (extensive margin).  相似文献   
35.
Objective: In Japan, the National Immunization Program (NIP) includes PPV23 as the primary vaccination for adults and catch-up cohorts. The Japanese Association for Infectious Diseases recommends revaccination for older adults who received primary vaccination ≥5 years earlier. The cost-effectiveness of adding revaccination and/or continuing catch-up vaccination in the NIP was evaluated from the public payer perspective in Japan.

Methods: The Markov model included five health states: no pneumococcal disease, invasive pneumococcal diseases (IPD), non-bacteremic pneumococcal pneumonia (NBPP), post-meningitis sequelae, and death. Cohorts of adults aged 65–95 were followed until age 100 or death: 2014 cohort (aged 65–95, vaccinated: 2014); 2019 cohort (aged 65: 2019); and 2019 catch-up cohort (aged 70–100: 2019, unvaccinated: 2014). Strategies included: (1) vaccinate 2014 and 2019 cohorts; (2) vaccinate 2014 and 2019 cohorts and revaccinate both; (3) strategy 1 and vaccinate 2019 catch-up cohort; (4) strategy 2 and vaccinate 2019 catch-up cohort; and (5) strategy 4 and revaccinate 2019 catch-up cohort. Parameters were retrieved from global and Japanese sources, costs and QALYs discounted at 2%, and incremental cost-effectiveness ratios (ICERs) estimated.

Results: Strategy 1 had the highest number of IPD and NBPP cases, and strategy 5 the lowest. Strategies 3–5 dominated strategy 1 and strategy 2 was cost-effective compared to strategy 1 (ICER: ¥1,622,153 per QALY gained). At a willingness-to-pay threshold of ¥5 million per QALY gained, strategy 2 was cost-effective and strategies 3–5 were cost-saving compared to strategy 1.

Conclusions: Strategies including revaccination, catch-up, or both were cost-effective or cost-saving in comparison to no revaccination and no catch-up. Results can inform future vaccine policies and programs in Japan.  相似文献   
36.
疫苗作为新冠疫情防控的最关键手段之一,已在各国抗疫中发挥积极影响。疫苗研发、生产、注射意愿以及全球分配的公平性与可及性等一系列问题日益受到世界关注。分析全球治理改革中,疫苗作为一种全球公共产品的创新治理问题,讨论疫苗产业发展特征与创新规律演化,剖析西方国家疫苗产业创新治理困境以及“竞争丛林”逻辑,阐释中国行动方案及对全球治理改革的贡献。最终提出疫苗产业创新治理机制对推动全球治理改革的政策含义。  相似文献   
37.
在全面实施创新驱动发展战略的时代背景下,揭示中国高端装备制造业自主技术创新效率稳定性,测度相关因素的影响强度与方向,对揭示中国高端装备制造业自主技术创新规律,制定其发展策略具有重要指导意义。聚焦中国高端装备制造业自主技术创新效率稳定性及影响因素,采用DEA-Malmquist指数方法和Tobit回归模型进行实证研究,结果表明,中国高端装备制造业自主技术创新效率存在一定波动性,且各细分行业技术创新效率内部稳定性较差,产业自主技术创新效率整体稳定性不高;自主技术创新投入因素和环境影响因素对产业自主技术创新效率的影响具有较高的异质性,其中创新资金投入和人力资源投入对自主技术创新综合效率、纯技术效率及规模效率具有正向影响,而新产品开发投入和企业规模对自主技术创新综合效率、纯技术效率和规模效率的影响具有异质性,政策因素与市场因素分别具有显著和非显著负向影响,外源性创新因素具有显著正向影响,且影响强度较大。在此基础上,提出调整政府对高端装备制造业创新支持模式、加强外源性创新与智力引进等策略建议。  相似文献   
38.
ABSTRACT

This article identifies the breakdowns in the covariance of three benchmark crude oil futures markets (WTI, Brent and Dubai) and investigates the changes of market connectedness across the breakdown periods. As the crude oil futures are traded in different regions, this article eliminates the non-synchronous trading data by employing the Vector Moving Average structure and the Bayesian data augmentation approach, which keeps the integrity of original data without changing its properties. The results show that there are significant breaks in the covariance structure of crude oil futures markets. The breakdown periods are consistent with the periods when the market volatilities are at high level and the returns are volatile. The changes of market connectedness are independent of the covariance states, which supports the globalization hypothesis for the crude oil market. The results also suggest that there is more information flow out of the WTI than to the WTI during the sample period, particularly during the breakdown periods in 2008–2009.  相似文献   
39.
Rating agencies produce ratings used by investors, but obtain most of their revenue from issuers, leading to a conflict of interest. We employ a unique data set on the use of non-rating services, and the associated payments, in India, to test if this conflict affects ratings quality. Agencies rate issuers that pay them for non-rating services higher (than agencies not hired for such services). Such issuers also have higher default rates. Both effects are increasing in the amount paid. These results suggest that issuers which hire agencies for non-rating services receive higher ratings despite having higher default risk.  相似文献   
40.
正2017年12月16日,韩国总统文在寅一行访问重庆。一天时间,他参观大韩民国临时政府旧址陈列馆,探寻中韩在渝共同抗击日寇的历史足迹,出席中韩产业合作重庆论坛,参观考察北京现代重庆工厂,为中韩经贸合作加油鼓劲。位于渝中区七星岗莲花池38号的大韩民国临时政府旧址陈列馆,是目前中国境内规模最大的涉朝鲜半岛遗址地。1940年至1945年,著名韩国独立运动家金九领导韩国临时政府在这里开展民族独立运  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