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   4886篇
  免费   68篇
  国内免费   36篇
财政金融   118篇
工业经济   715篇
计划管理   2013篇
经济学   353篇
综合类   315篇
运输经济   94篇
旅游经济   47篇
贸易经济   550篇
农业经济   417篇
经济概况   368篇
  2024年   13篇
  2023年   37篇
  2022年   101篇
  2021年   139篇
  2020年   116篇
  2019年   44篇
  2018年   61篇
  2017年   83篇
  2016年   145篇
  2015年   180篇
  2014年   668篇
  2013年   551篇
  2012年   605篇
  2011年   558篇
  2010年   435篇
  2009年   268篇
  2008年   225篇
  2007年   215篇
  2006年   160篇
  2005年   110篇
  2004年   79篇
  2003年   57篇
  2002年   39篇
  2001年   29篇
  2000年   24篇
  1999年   18篇
  1998年   9篇
  1997年   1篇
  1996年   6篇
  1995年   3篇
  1994年   4篇
  1993年   3篇
  1992年   1篇
  1990年   1篇
  1988年   1篇
  1981年   1篇
排序方式: 共有4990条查询结果,搜索用时 0 毫秒
121.
专业合作社成员在空间分布上呈现出明显的地缘性特征,使得合作社对生猪质量控制具有天然的优势,但仍无法避免成员“搭便车”的困境。文章以奥尔森的集体行动理论为指导,设计了选择性激励、允许成员异质性以及强制措施等治理机制,并通过对金诚众和合作社的案例分析,提出扶持合作社进行生猪品牌建设,提高生猪抽检比例,加强猪肉产品的认证管理等政策建议。  相似文献   
122.
以长沙市消费者的调查数据为例,剖析了长沙市消费者对安全认证农产品的认知情况、接受意愿、支付意愿和实际的购买行为及其相关影响因素。结果表明:消费者对农产品质量安全的关注程度较高,但对安全认证农产品的认知程度较低、信任度较低。消费者的收入水平、消费者对安全农产品的认知程度、受教育水平以及对政府的信任等均会不同程度地影响消费者对安全认证农产品的购买意愿与行为。  相似文献   
123.
The complex interactions between the determinants of food purchase under risk are explored using the SPARTA model, based on the theory of planned behaviour, and estimated through a combination of multivariate statistical techniques. The application investigates chicken consumption choices in two scenarios: (a) a ‘standard’ purchasing situation; and (b) following a hypothetical Salmonella scare. The data are from a nationally representative survey of 2,725 respondents from five European countries: France, Germany, Italy, the Netherlands and the United Kingdom. Results show that the effects and interactions of behavioural determinants vary significantly within Europe. Only in the case of a food scare do risk perceptions and trust come into play. The policy priority should be on building and maintaining trust in food and health authorities and research institutions, while food chain actors could mitigate the consequences of a food scare through public trust. No relationship is found between socio‐demographic variables and consumer trust in food safety information.  相似文献   
124.
This article analyzes the productivity growth of the Spanish dairy processing industry from 1996 till 2011, which concerns the period of increased EU regulation regarding food safety as well as economic crisis. Data envelopment analysis is used to compute the Malmquist index and its components. The results suggest that productivity on average declined during the period under investigation. The decomposition of the Malmquist index finds that technical regress contributed to productivity decline despite improvements in technical and scale efficiencies. Our results also suggest that food safety regulations did not have a negative impact on productivity growth. Technical change and scale efficiency change made significant negative contributions to productivity growth in the period under crisis, whereas firms significantly improved their technical efficiency in that period.  相似文献   
125.
Childhood drowning remains a serious public health problem worldwide. The Australian Water Safety Council has set as one of its highest priorities the reduction of drowning deaths in children aged 0–14 years. However, concerns have recently been raised that many students completing primary school still lack the ability to recognize potential aquatic risks, cope with emergencies or assist someone else in danger. In this study, 107 primary school children aged 11–12 completed a one day training programme led by surf lifesaving instructors. Pre, post and eight week follow-up measures showed statistically significant improvements in recognition of the red ‘beach closed’ flag, aquatic safety signs, how to identify a rip current and choosing the safest place to swim at a beach that included a rip current in the picture. Following training students were more willing to provide first aid assistance to family members and friends in an emergency situation. Findings reinforce the value of school-based training that provides a general foundation for aquatic safety, with the caveat that current programmes must be evaluated to ensure their content has a robust prevention focus.  相似文献   
126.
Runway incursions are an important aviation safety concern; between 2002 and 2015 there were 16,785 runway incursions at United States airports ranging in size from small general aviation (GA) to large commercial airline hubs. When examining airports with the 50 highest incursion count over the past 5 years, the predominant categories were large hubs, which accounted for 21 airports and general aviation (GA) airports which accounted for 16 airports. In June 2015, the Federal Aviation Administration (FAA) announced the Runway Incursion Mitigation (RIM) program to identify airport risk factors that might contribute to a runway incursion and develop strategies to help airport stakeholders mitigate those risks. Different size airports serve different aircraft fleets, serve different operating volumes, and have different resources available (both funds and technologies) for incursion mitigation. Therefore, it is valuable to determine the correlating factors that affect incursions at different size airports. This paper uses econometrics based modelling techniques to identify statistically significant factors in data provided by the (FAA) public web sites on runway incursions. The model identified statistically significant variables that correlate with incursions, based on severity, for airports categories defined by the National Plan of Integrated Airport Systems (NPIAS).The model results indicate that operational incidents (OI) are more likely at large hub airports. In contrast, at GA/non-hub airports, pilot deviations (PD) were significant for less severe incursions (severity C and D). Only one variable, “number of years since 2002”, was found to be significant for all the three airport categories; this variable was correlated with severity A incursions and indicated a statistically significant reduction in severity A incursions, despite an overall 80% increase in incursions between 2002 and 2015.  相似文献   
127.
中部槽是刮板机最主要部件之一,作为矿山机械刮板输送机的机身。数量最多占比最大,是煤炭输送的通道。由于工件重量较重,目前喷漆采用人工油漆喷涂,人工喷涂不均匀,漆膜厚度不一致,油漆存在人员污染问题。结合现有喷漆闪锈与产品锈蚀问题,对水性漆防沉淀、耐候耐水性、闪锈、起皱与漆裂等进行研究及实验。研究出一种可在产品锈蚀状态下使用的中部槽水性快干专用漆。  相似文献   
128.
通过IPSEC技术,把移动IP和防火墙联系到一起,利用IPSEC保护移动IP的安全性。防火墙体系结构是边界防火墙结合IPSEC安全网关,因此防火墙本身具有识别IPSEC数据包的功能,使具有IPSEC保护的移动IP数据可以安全地通过防火墙,而IPSEC本身是安全的协议,所以在移动IP穿越防火墙的同时,也可以保证家乡网络的安全性。  相似文献   
129.
测试砖坯和成型砖的品质参数,研究优化砂岩质煤矸石原料的颗粒级配对其制作烧结制品的影响.得出制砖所需的最佳颗粒级配;对不同温度段的烧结制品进行物理力学性能检测,分析比较其烧结温度制度对制品质量的影响,得出较佳的焙烧温度,为砂岩质煤矸石资源化利用提供可靠的工艺参数。  相似文献   
130.
传统城市化理论往往强调自然资源对城市发展的正面作用,却对城市化的约束和反向作用问题考虑不够。文章基于"资源尾效"和"资源诅咒"两种假说,利用1997-2012年中国27个典型煤炭城市的数据对其煤炭资源开发与城市化发展的关系进行正负效应检验。结果表明:27个煤炭城市中有16个城市出现"资源尾效",其尾效数值为0.001 755;其余11个城市出现"资源诅咒",其煤炭资源对城市化发展的影响系数为-0.207 2。可见,自然资源的开发强度要处于一个合适的水平,并同时注意资本投入、教育和制度等因素才能最大程度上提高城市化水平。  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