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   82127篇
  免费   3560篇
  国内免费   1895篇
财政金融   4781篇
工业经济   3245篇
计划管理   16484篇
经济学   10883篇
综合类   9591篇
运输经济   798篇
旅游经济   1668篇
贸易经济   8519篇
农业经济   5535篇
经济概况   8293篇
水利工程   17785篇
  2024年   289篇
  2023年   1027篇
  2022年   1511篇
  2021年   2267篇
  2020年   2654篇
  2019年   1942篇
  2018年   1831篇
  2017年   2245篇
  2016年   2573篇
  2015年   2732篇
  2014年   5975篇
  2013年   6500篇
  2012年   6864篇
  2011年   8230篇
  2010年   5951篇
  2009年   5227篇
  2008年   5318篇
  2007年   4857篇
  2006年   4371篇
  2005年   3490篇
  2004年   2547篇
  2003年   2070篇
  2002年   1504篇
  2001年   1347篇
  2000年   1018篇
  1999年   665篇
  1998年   452篇
  1997年   390篇
  1996年   343篇
  1995年   261篇
  1994年   241篇
  1993年   181篇
  1992年   151篇
  1991年   83篇
  1990年   43篇
  1989年   64篇
  1988年   33篇
  1987年   18篇
  1986年   12篇
  1985年   58篇
  1984年   85篇
  1983年   65篇
  1982年   43篇
  1981年   14篇
  1980年   17篇
  1979年   14篇
  1978年   2篇
  1977年   6篇
  1973年   1篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
1.
为检查工程质量,查找输水系统可能存在的问题并消除隐患,保障电站安全运行,福建仙游抽水蓄能电站在投产发电前,要对输水发电系统进行充水试验与放空排水试验,在试验过程中监测输水系统的应力、应变与渗漏水情况。本文以尾水系统为例,介绍了试验所应具备的工程条件、工作程序及技术要求、试验成果分析和存在问题处理等。试验表明,仙游抽水蓄能电站尾水系统设计合理,施工质量优良,结构可靠,可供同类工程参考与借鉴。  相似文献   
2.
文章通过对黑龙江省高效节水现状,存在问题的分析,结合黑龙江省高效节水发展的支撑能力,阐述黑龙江省节水增粮目标、任务及总体布局,为黑龙江省2012—2015年节水增粮实施提供依据。  相似文献   
3.
In this article, we investigate the existence of long-run common trends between imports and remittances in 11 Central and Eastern European countries which are part of the European Union. Using the Engle–Granger two-step procedure, we determine that for all countries in our sample there are no long-run common trends (no cointegration) between imports and remittances. However, the results are mixed when running a Granger causality test. For nine countries, we can establish either a bidirectional or unidirectional Granger causality, indicating that past values of one variable have predictive content on the other variable. In two countries, there is no Granger causality between imports and remittances.  相似文献   
4.
Are poor macroeconomic outcomes primarily the result of economic policies, or of deeper underlying state fragility problems in sub‐Saharan Africa? We attempt to answer this question by using carefully specified dynamic panel regression techniques to show how state fragility conditions help to explain the differences in the macroeconomic performance of sub‐Saharan African economies, and to identify the most plausible mechanisms of transmission. We find that countries with greater fragility suffer higher macroeconomic volatility and crisis; they also experience weaker growth. When we disaggregate state fragility into its various components, we find that it is the security and social components that have the strongest causal impact on macroeconomic outcomes, while the political component is, at best, weak. Therefore, we conclude that it is state fragility conditions, and not necessarily macroeconomic policies, that are of first‐order importance in explaining the differences in macroeconomic performance for African countries. The knock‐on effects are mostly mediated through the fiscal channel, the aid channel, and the finance channel. Accordingly, we recommend that interventions in fragile states should best focus on exploiting the potential for using fiscal policy, aid, and finance as instruments to improve macroeconomic outcomes in sub‐Saharan Africa.  相似文献   
5.
Advocates of public‐private partnerships (PPPs) argue that they can deliver public infrastructure more efficiently than traditional procurement through timelier completion and superior value for money. Despite these claims comparative analysis of the performance of both procurement methods has received scant attention in the PPP literature to date. This paper addresses this issue by providing an in‐depth, case‐based comparison of PPP versus traditional procurement in the schools sector in Ireland. Through detailed semi‐structured interviews with key stakeholders and an examination of the available documentation, we assess whether the key objectives of using PPP have been achieved. Overall, we find no evidence that PPP leads to faster delivery of infrastructure when the overall procurement process from contract notice to delivery is accounted for. In addition, we find only limited evidence to suggest that PPP results in better value for money.  相似文献   
6.
The empirical literature on farmer cooperatives is now fast emerging and developing in the areas of performance, ownership and governance, finance, and member attitude. We discuss 56 peer‐reviewed publications to illustrate the main findings and conclusions while outlining challenges and opportunities for future research. Generally, cooperative membership is found to positively impact price, yield, input adoption, income, and other indicators of member performance, yet there is growing evidence of an uneven distribution of benefits for small and large producers. In terms of structure, evidence of a causal relationship of ownership and governance to performance has been elusive, yet there are now many findings of inherent equity and long‐term debt constraints, often in the context of consolidation to drive scale and scope economies. Further inefficiency is observed to be driven by increased heterogeneity in member attitudes and objectives, in particular in terms of commitment and participation. Thus, overall, empirical work portrays farmer cooperatives as flawed and complex business organizations which nonetheless have a strong positive impact on its members. While applied research may progress in various directions, a general improvement in empirical methodologies is needed to allow robust analysis of mixed objectives in dynamic environments.  相似文献   
7.
文中分析了大同市水资源开发利用的状况,并对水资源承载能力的有关问题进行了讨论。  相似文献   
8.
根据某面板堆石坝施工期、蓄水初期以及几年来的沉降观测资料,对坝体填筑材料计算参数进行反馈分析,得出了能够反映坝体实际变形的弹塑性应力变形计算参数,有利于今后建立大坝变形预报模型,更准确地把握大坝实时运行状态。  相似文献   
9.
面对浩如烟海的网络信息资源丰富又无序、新颖又形象、急需开发利用。本文探讨了开发利用网上信息资源的必要性,介绍了如何开发利用网上信息资源,为用户充当网络信息导航员,发掘网上信息,丰富现有信息源等几种方法。  相似文献   
10.
21世纪 ,企业面临“非连贯性”的新竞争环境 ,需要建立健全企业人才资源开发与管理的机制和相应的策略。本文在分析企业面临的新形势的基础上 ,对当前企业人力资源开发与管理机制进行了分析 ,并进一步提出企业人力资源开发与管理的相应策略 ,即彻底转变和更新人才观念 ;实施战略性人力资源管理 ;建立企业高素质人才资源开发机制等。  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