全文获取类型
收费全文 | 4362篇 |
免费 | 446篇 |
国内免费 | 201篇 |
专业分类
财政金融 | 178篇 |
工业经济 | 193篇 |
计划管理 | 425篇 |
经济学 | 475篇 |
综合类 | 292篇 |
运输经济 | 19篇 |
旅游经济 | 54篇 |
贸易经济 | 640篇 |
农业经济 | 334篇 |
经济概况 | 247篇 |
水利工程 | 2152篇 |
出版年
2024年 | 22篇 |
2023年 | 77篇 |
2022年 | 84篇 |
2021年 | 113篇 |
2020年 | 139篇 |
2019年 | 150篇 |
2018年 | 117篇 |
2017年 | 173篇 |
2016年 | 167篇 |
2015年 | 180篇 |
2014年 | 257篇 |
2013年 | 334篇 |
2012年 | 343篇 |
2011年 | 346篇 |
2010年 | 245篇 |
2009年 | 242篇 |
2008年 | 291篇 |
2007年 | 261篇 |
2006年 | 274篇 |
2005年 | 258篇 |
2004年 | 160篇 |
2003年 | 155篇 |
2002年 | 135篇 |
2001年 | 93篇 |
2000年 | 83篇 |
1999年 | 60篇 |
1998年 | 45篇 |
1997年 | 44篇 |
1996年 | 41篇 |
1995年 | 44篇 |
1994年 | 29篇 |
1993年 | 21篇 |
1992年 | 14篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
排序方式: 共有5009条查询结果,搜索用时 15 毫秒
1.
This study aims to examine the motives behind retailers’ post-entry expansion in foreign markets. Through case studies of eleven participating luxury fashion retailers in China, qualitative data was collected from twenty-two executive interviews. Although their initial market entry was driven by both reactive (push) and proactive (pull) factors, the motives behind their post-entry expansion have become predominantly proactive, especially long-term growth strategies, the ambition to extend their brands and retail formats to more cities, and the experiences gained in entry markets. The desire to optimize the retail store portfolio through multiple channel strategies have slowed down the expansions of physical stores. 相似文献
2.
ABSTRACTNatural language query systems over RDF data need to rely on the semantic relations in query. First, we propose the new crowdsourcing model that used to produce semantic relations dataset. The model not only inherits completeness of the iterative model and accuracy of the parallel model, but also saves human resources. Second, we mine the rules of semantic relation recognition from the correlations between dependency structures and semantic relations. Third, we propose an algorithm of semantic relation recognition for natural language query over RDF data, and experiments demonstrate that it can recognize more semantic relations than existing methods. 相似文献
3.
作为国有企业产权改革主要模式,“混合所有制”改革是否有助于确保国有资产保值增值,是否有助于推动中国经济可持续发展等问题仍存在探讨空间。本文基于对于改革开放以来中国国有企业改革的成就和教训的考察,指出“混合所有制”可以作为竞争性部门国有企业改革的一个过渡形式;对于垄断央企的改革应该充分借鉴国际上自然垄断行业的改革经验,打破行政垄断,推动竞争性框架建立,并切实实现从“管企业”逐步调整为“管资本”,通过改革实现国有资产的保值增值,并为经济创造新的增长点。 相似文献
4.
5.
6.
7.
The planimetric shifts in channel location of large alluvial rivers are a critical component in the creation of diverse structures and functions in riverine habitats. Engineered management schemes must also compensate for this type of channel change to protect resources and maintain navigation channels. The stability of the Lower Mississippi River channel was assessed through an analysis of historical records of channel position produced and archived by the United States Army Corps of Engineers. Channel location was recorded for the years 1765, 1820, 1881, 1915, 1930, 1937, 1960 and 1970. Channel stability was measured by two introduced metrics on a cell‐by‐cell basis: (1) the standard deviation of Euclidean distance to a channel cell for the entire period of record, and (2) the rate of Euclidean distance change between years in the period of record. At a coarse spatial scale, channel instability increased in the downstream direction. The variability of channel stability also increased in the downstream direction. Analysis of this variability identified alternating areas of high and low stability occurring with greater frequency as distance downstream increased. These findings are validated by past studies of channel stability along the Lower Mississippi River. As a result, the proposed metrics provide a consistent, quantitative, efficient and cost‐effective means of identifying areas of channel instability at several spatial scales. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
8.
各向异性厚板固有频率的精确解 总被引:3,自引:0,他引:3
该文抛弃薄板理论的位移和应力假设,利用矩阵分析和三维弹性动力学理论,导出四边简支各向异性厚板的固有频率方程。该方法可推广应用于各向异性层合板动力分析。 相似文献
9.
高晓梅 《水利水电工程设计》2002,21(4):1-4
永定新河是天津市防洪的北部防线。由于受海相来沙淤积 ,河道行洪能力大幅度下降。针对永定新河治理工程设计中涉及到的河道淤积治理方案、闸位比选、防潮闸结构型式及施工方法、闸下减淤清淤措施等诸多问题进行了分析和研究 ,提出了相应的措施和建议 相似文献
10.
在不同频率流量和阻水程度条件下,采用一维明渠非恒定流网河数学模型,分析规划中的佛山市桥梁群对区间河道洪季行洪、枯季水环境的影响,计算洪季不同频率洪峰流量下规划桥梁群对区间河道行洪洪水位、分流比的影响,枯季时规划桥梁群对区间河道过流量、分流比的影响,结果表明,利用一维网河数学模型计算佛山市中心组团规划桥梁群对区间河道断面平均水位、流量和流速的影响,结果有足够的数值精度,是可信的。 相似文献