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   2936篇
  免费   150篇
  国内免费   41篇
财政金融   80篇
工业经济   164篇
计划管理   852篇
经济学   457篇
综合类   272篇
运输经济   187篇
旅游经济   82篇
贸易经济   410篇
农业经济   327篇
经济概况   296篇
  2024年   11篇
  2023年   48篇
  2022年   50篇
  2021年   92篇
  2020年   145篇
  2019年   90篇
  2018年   70篇
  2017年   116篇
  2016年   104篇
  2015年   100篇
  2014年   247篇
  2013年   295篇
  2012年   266篇
  2011年   273篇
  2010年   223篇
  2009年   176篇
  2008年   189篇
  2007年   142篇
  2006年   124篇
  2005年   100篇
  2004年   69篇
  2003年   59篇
  2002年   28篇
  2001年   37篇
  2000年   9篇
  1999年   13篇
  1998年   15篇
  1997年   4篇
  1996年   9篇
  1995年   5篇
  1994年   2篇
  1993年   2篇
  1991年   2篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1984年   4篇
  1983年   1篇
  1982年   2篇
  1980年   1篇
排序方式: 共有3127条查询结果,搜索用时 328 毫秒
41.
在知识经济的背景下,吸收能力被认为是企业提升绩效和增强创新的战略能力.社会网络被认为可以对潜在的吸收能力和实现的吸收能力都产生积极影响.本文从社会网络的关系层面,从外部和内部两个视角,分别阐述了社会网络如何影响吸收能力的两个维度.本文还从提升吸能力的视角,提出了有效构建和维护社会网络的措施.  相似文献   
42.
Deaths, injuries and disabilities resulting from road traffic injuries (RTIs) are a public health major concern. This study aims to calculate the burden of RTIs in Kermanshah Province in Iran. In this study to determine the years of life lost (YLL) related to RTIs, the National Death Registration and Forensics Medicine census data were employed. We use forensic medicine data to calculate the incidence of non-fatal injuries and years lost due to disability (YLD). The cause of death and non-fatal injuries was classified using ICD-10 codes and 23 groupes of global burden of diseases (GBD) 2010. The disability-adjusted life year (DALY) estimated on the guidelines of the GBD 2010 and age and sex structure was taken from the National Statistic Center for the year 2010. Overall, 70.8% of the subjects were males. The fatal and non-fatal injury rates of RTI were 51.3 and 283.6 per 100,000 persons, respectively. YLLs and YLDs were 46613 (24.5 per 1000) and 3405 (1.8 per 1000) in both sexes, respectively. The disability adjusted life years were 40711 in males, 9306 in females and 50018 in both sexes (42.5, 9.8 and 26.3 per 1000, respectively). More than 93% of DALY was from YLL (24.5 per 1000), with a small proportion for YLD (1.8 per 1000). Accounting for more than 50,000 DALY attributed to RTIs, traffic injuries is a major public health and socioeconomic problem in Kermanshah. Designing cost-effective interventions based on comprehensive and multi-sectoral programmes at the national and provincial levels can save many lives and resources that are lost every year. Undoubtedly, establishing a surveillance system at the sub-national level and measuring the burden of injuries, as in this study, can help policy-makers and planners in lessening the burden of RTIs.  相似文献   
43.
黄红梅 《价值工程》2014,(32):242-243
本文通过全面剖析影响交通冲突的原因,以交通流量、道路几何设计和道路环境三方面的因素建立指标层次结构体系。提出基于模糊层次分析(FAHP)法优化BP神经网络(BPNN)的预测模型,应用于交通冲突预测。  相似文献   
44.
Firms undertaking independent and cooperative research and development (R&D) activities simultaneously often have difficulties to realise their synergistic effects. This study contends that such difficulties are caused by tensions between two types of R&D activities in terms of resource competition and knowledge leakage. Moreover, organisational slack and absorptive capacity may affect these tensions and thereby play important role in synergizing independent and cooperative R&D activities. Based on a survey data of 286 firms, this study finds that such two types of R&D activities jointly have a negative impact on firm performance. Furthermore, organisational slack aids in synergizing them, while absorptive capacity has an adverse impact. These findings enrich our knowledge on the interrelation of independent and cooperative R&D activities and shed light on how firms can synergize them.  相似文献   
45.
Current results of direct relationships between collaboration and innovation capability on performance in tourism contexts are inconsistent. This research is to uncover roles of collaborative routines on promoting relationships between internal and service innovation capabilities as two distinct mechanisms, and performance. The study also examines the contingent effect of knowledge search on performance. Survey data from 181 samples from the Thai tourism industry are gathered for analyses. Findings demonstrate that knowledge search and internal innovation capability have a direct impact on performance, whereas the effect of service innovation capability on performance is significant only in the presence of collaborative routines.  相似文献   
46.
This article examines the effects of excess capacity on the production cost and technical inefficiency of hotels and restaurants in Norway. The dataset includes a daily unbalanced panel of 94 hotels and restaurants from 2003 to 2014. To accommodate inefficiency, we use an input distance function (IDF). Inefficiency in the IDF means that if inputs are overused by k% then production cost is also increased by k%. We also allow inefficiency to differ across locations and regions by using them as determinants. The results indicate that excess capacity considerably affects the cost and increases inefficiency. The marginal effect on cost increases with excess capacity, but the effect on inefficiency sets in when it exceeds 50 percent. Furthermore, we find less overuse of inputs by firms in small metro towns and the Northern region causing them to be more efficient [except for the Southern and Western regions] than their counterparts.  相似文献   
47.
文章从多分辨率交通仿真的建模过程入手,研究了系统仿真的校核、验证与确认(Verification Validation Accreditation,VVA)过程评价的原理。在此基础上,提出了基于VVA的多分辨率交通仿真建模的过程评价框架。通过研究仿真系统生命周期中的一系列活动来评价研究结果的正确性和有效性,提高了系统的可信性,使仿真系统能够满足实际应用的需要。  相似文献   
48.
This paper discusses the situation of China's air cargo sector facing the COVID-19 pandemic. Based on the expectation that it can go out of recession more easily than China's air passenger sector, this paper analyzes four aspects that are favorable and unfavorable for its further development: (1) strengths (China's sustainable economic basis and proliferating cargo suppliers), (2) weaknesses (insufficient cargo capacity and less business internationalization), (3) opportunities (top authority support, rising e-commerce demand, and new technological momentum), and (4) challenges (uncertain trade environment and increasing profitability pressure). Then this paper suggests strategies for China's air cargo suppliers to adapt to the pandemic.  相似文献   
49.
郑火胜 《价值工程》2014,(26):277-278
日益激烈的人才竞争对学生的就业能力提出了新的、更高层次的要求,通识知识的学习是培养学生的人文素质和综合职业素质的重要途径和方法,本文通过对通识知识学习的深入分析,探讨了通识学习对于提高学生就业能力的影响和意义。  相似文献   
50.
徐明杰  韩印 《物流科技》2020,(1):106-110
为了合理地优化交叉口信号配时,通过分析交叉口的评价指标,建立了以车辆的平均延误、停车次数最小、交叉口整体通行能力最大、各相位有效绿灯时间和交叉口周期时长作为约束条件的数学模型。并通过改进前人研究基础上的动态加权系数,将多目标的非线性优化问题转化为单一目标的非线性规划问题,为了得出更科学稳定的解,提出了改善粒子群算法系统稳定性的2种方法,并将其与粒子群算法结合起来。然后以Matlab为求解工具,结合临邑市某一交叉口实例进行求解分析。最后的结果表明,在使用改进后的粒子群算法进行优化后交叉口通行能力较之现状提升了9%,延误下降了28%,停车次数下降了9%,且各项优化结果均优于Webster,改进后的算法在程序中运行300代,到216代才开始收敛,而未改进的算法稳定性较差,优化结果和收敛曲线则随着实验次数的变化而变化,最后的结论证明了该算法和模型的可靠性。  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