全文获取类型
收费全文 | 281篇 |
免费 | 13篇 |
专业分类
财政金融 | 29篇 |
工业经济 | 25篇 |
计划管理 | 126篇 |
经济学 | 31篇 |
综合类 | 14篇 |
运输经济 | 6篇 |
旅游经济 | 1篇 |
贸易经济 | 29篇 |
农业经济 | 14篇 |
经济概况 | 19篇 |
出版年
2023年 | 10篇 |
2022年 | 3篇 |
2021年 | 11篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 14篇 |
2016年 | 7篇 |
2015年 | 24篇 |
2014年 | 40篇 |
2013年 | 22篇 |
2012年 | 28篇 |
2011年 | 28篇 |
2010年 | 14篇 |
2009年 | 12篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 11篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有294条查询结果,搜索用时 17 毫秒
11.
12.
13.
《Enterprise Information Systems》2013,7(3):287-299
A thorough study of X party material flow (XPMF), its theory and its applications is conducted in this research. The X material flow concept is an extension of the material flow (MF) theory. To further elucidate that XPMF is one type of MF service model with PMF (party, material, flow) fractal structure and the characteristics of XPMF, we develop the three-pyramid synergetic operational model of XPMF. Through the analysis of several cases, we believe that OIR (Objective relational grade, Information sharing grade, and Resource complementary grade) is the set of order parameters that control and determine the formation of XPMF new structure and its degree of being ordered. Therefore it reveals the mechanism of XPMF formation and evolution. We also provide the principles and the methods for XPMF control. 相似文献
14.
工件的某些表面形貌特征会对产品的性能和质量产生重大的影响,因此,拓展表面形貌特征的评定参数,以提升产品的质量监控水平已成为必需。文章以工件的回转密封面为例,就螺线纹理这一表面微观结构的形貌特征及其可能引起的产品质量隐患做了详细的说明,并介绍了如何利用精密仪器实施相关的测量。文中透过对这一往往被业内忽略的细节的监控思路,阐明了在企业内,强化质量意识必须从重视每个细节做起的观点。 相似文献
15.
本文通过哈尔滨地铁一期工程的实例,介绍了预钻式旁压试验在工程中的现场操作,成果分析及应用。 相似文献
16.
17.
18.
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
19.
为解决集约化养殖造成的严重环境污染和农村一次能源短缺的问题,设计开发一种混流、折流、推流相结合的湿法沼气发酵系统,通过对系统的运行试验,对该沼气发酵的工艺流程进行适当的调整,并对该工艺条件下的系统运行参数进行实验研究,优化各操作参数以提高该工艺的整体运行效果,实现沼气发酵系统的节能、低耗、高效运行。 相似文献
20.
针对如何正确选择浪涌保护器,提高建筑物防雷水平,文章概述了浪涌保护器的有关知识,阐述了浪涌保护器设计和选择的步骤。 相似文献