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   29561篇
  免费   1141篇
  国内免费   483篇
财政金融   2095篇
工业经济   1292篇
计划管理   7939篇
经济学   4103篇
综合类   5710篇
运输经济   204篇
旅游经济   241篇
贸易经济   3388篇
农业经济   2145篇
经济概况   4067篇
信息产业经济   1篇
  2024年   33篇
  2023年   157篇
  2022年   311篇
  2021年   476篇
  2020年   598篇
  2019年   323篇
  2018年   271篇
  2017年   383篇
  2016年   446篇
  2015年   773篇
  2014年   2077篇
  2013年   1738篇
  2012年   2541篇
  2011年   3279篇
  2010年   2605篇
  2009年   2223篇
  2008年   2479篇
  2007年   2304篇
  2006年   2267篇
  2005年   1679篇
  2004年   1296篇
  2003年   894篇
  2002年   605篇
  2001年   484篇
  2000年   337篇
  1999年   175篇
  1998年   74篇
  1997年   65篇
  1996年   41篇
  1995年   24篇
  1994年   33篇
  1993年   35篇
  1992年   25篇
  1991年   9篇
  1990年   11篇
  1989年   10篇
  1988年   2篇
  1987年   6篇
  1986年   1篇
  1985年   19篇
  1984年   29篇
  1983年   15篇
  1982年   13篇
  1981年   4篇
  1980年   4篇
  1979年   2篇
  1978年   3篇
  1977年   5篇
  1973年   1篇
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
41.
In this article we use the innovation survey of the manufacturing industry of Peru to identify cooperation behaviors for research and development (R&D) projects among companies and external agents in general. Likewise, we also find cooperation behaviors among the industry and the following external agents: university, technical centers, suppliers, customers, and companies of the same group, competitors, guilds, and consultants. Within the specific agents, the university is considered a cooperation agent for R&D projects. We use the survey of innovation in the manufacturing industry of Peru conducted in 2015, which resulted in 1447 Peruvian companies being surveyed. Evidence was obtained as to the degree of the tie between the industry and external agents for cooperation in R&D projects, giving relevance to variables such as investment, resources, and degree of innovation. Our results show that investment is an important factor for cooperation with external agents. Additionally, companies that have innovated at some point seek to cooperate with external agents. Finally, the importance of the university is demonstrable, thus, companies that invest in R&D seek to cooperate with the university.  相似文献   
42.
The paper examines the effect of population ageing on public education spending. On the one hand, ageing is expected to have a negative effect on education, as an increasing number of retirees results in ‘intergenerational conflict’ and, hence, the condemnation of education expenditure. On the other hand, ageing, in combination with pay-as-you-go pension systems, offers incentives for the working-age generation to invest in the public education of the young in order to ‘reap’ the benefits (that is, higher income tax/contributions) of their greater future productivity. Empirical evidence derived from the application of a fixed effects approach to panel data for OECD countries shows that the increasing share of elderly people has a non-linear effect on education spending. This indicates a certain degree of intergenerational conflict. Nevertheless, we find that future population ageing, which reinforces the mechanism linking public education and pensions, reflects positively on education expenditure. Furthermore, by disaggregating total education expenditure by educational levels, we observe that this effect is led by levels of non-compulsory education, probably as a reflection of the direct connection to labor productivity.  相似文献   
43.
针对当前摩托车单向器组件主要采用手工装配、装配效率低、随机性大、无法对装配过程实现有效管理控制的情况,为了易于对零件装配过程进行实时监测和提高生产效率,开发了一种智能摩托车单向器自动装配机。介绍了摩托车单向器自动装配机的上料系统、装配系统、检测系统和落料系统的机械结构,重点阐述了设备的气动系统设计,并进行了实验研究。结果表明,该设备可实现组成单向器的5种零件自动上料和装配,同时降低了操作人员的劳动强度,生产效率提高约50%。其气动系统噪音小、工作可靠,可应用于摩托车单向器的大批量生产。研究结果可为其他相似异形零件自动装配机的开发提供参考。  相似文献   
44.
以浙江电网企业转型现代能源综合服务的具体战略与发展规划为研究背景,针对能源综合服务系统的运行规划目标,开展基于运行规划的能源综合服务系统能效管理研究。从系统工程的视角出发,以能源流为纽带,基于多尺度能源系统建模方法,构建了能源综合服务系统模型,并结合系统综合能效,采用粒子群优化算法来优化系统各设备单元的运行策略,以实现基于运行规划的最优能效管理。通过能源综合服务系统模型计算表明,大规模清洁能源和可再生能源的接入,可以明显提高系统综合能效;随着区域用户总冷量和/或总热量需求占总电力需求的比值增大,系统最优综合能效逐渐增大;与使用内燃机、燃气轮机及汽轮机为原动机的热电联产系统相比,使用燃料电池为原动机的热电联产系统可以使能源综合服务系统综合能效更优。  相似文献   
45.
The boundary conditions of supply chain integration (SCI) have been widely studied in order to find out when SCI is applicable and effective. However, prior studies have mainly focused on external contextual factors, such as supply complexity, environmental uncertainty and country-level infrastructure. This study contributes to the SCI literature by examining the contingency effects of internal production systems on the relationship between supplier integration, customer integration and operational performance. Based on organizational information processing theory, we provide evidence to show that the impact of supplier and customer integration on operational performance varies across production systems, such as one-of-a-kind production, batch production and mass production systems. The empirical results also reveal how supplier and customer integration can be matched with different configurations of production systems in order to achieve the desired quality, flexibility, delivery or cost performance.  相似文献   
46.
针对现行水利建设市场主体信用评价指标体系,以施工单位为例,在比较分析已有信用评价结果的基础上,采用问卷调查统计方法,得到市场主体对现有评价指标的认同度,并分析不同指标认同度差异的原因,进而提出删除门户网站及平台信息、固定资产占总资产比例及施工年产值等认同度低的指标,提高管理层素质、人员素质及管理制度等认同度高的指标的权重。  相似文献   
47.
While most major reforms of health systems fail, those that succeed are motivated by politicians' quest for reducing the health burden on their budget in response to a shift in voters' preferences away from public health. An Edgeworth box is used to depict their preferences, in addition to those of (potential) patients and health‐care providers. Politicians are found to severely constrain the area of mutual advantage, suggesting that only minor reforms are possible unless they promise to lower health‐care expenditure. An efficiency‐enhancing change that would enlarge the box and hence the area of mutual advantage would be to suppress the requirement imposed on health insurers to purchase domestically, rather than being free to directly import health‐care services and drugs.  相似文献   
48.
根据供给侧结构性改革的背景和基本内涵,对水资源供给侧结构性改革的内涵进行研究,提出了狭义和广义的水资源供给侧结构性改革的内容。在分析水资源需求新形势的基础上,提出了水资源供给侧结构性改革的要求。根据水循环理论提出了水资源管理是推动水资源供给侧结构性改革的重要抓手,并在最严格水资源管理制度的基础上,提出了符合水资源供给侧结构性改革要求的水资源管理制度。  相似文献   
49.
This study explores the impact of governance and institutions on inbound tourism demand in Malaysia using a dynamic panel data approach for 45 tourism source countries over the period 2005–2015. The results show that institutions play a very important role in explaining the behaviour of inbound tourism demand. To obtain a better picture, we investigate the response of international tourists to disaggregated institutional quality. We find that international tourists are more concerned about political stability, governmental effectiveness, regulations, laws, and corruption than voice and accountability. Therefore, policymakers should focus on ways to improve institutional quality to significantly increase international tourist arrivals.  相似文献   
50.
针对机载三维音频应用的实时性需求,提出了一种基于单耳相对头相关传递函数和改进型混响模型的机载三维音频快速实现方法,在较传统实现方式性能无明显下降的情况下降低了80%的计算量。对提出的算法在F-16战斗机模拟强噪声环境下进行相关主观试听实验,同时在某型飞机音频系统中实验验证。实验结果表明,所提方法在实时处理3路三维音频时,三维音频方位分辨精度在5°以内,可满足实际机载平台使用需求。  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