全文获取类型
收费全文 | 7800篇 |
免费 | 920篇 |
国内免费 | 820篇 |
专业分类
财政金融 | 329篇 |
工业经济 | 209篇 |
计划管理 | 821篇 |
经济学 | 421篇 |
综合类 | 385篇 |
运输经济 | 70篇 |
旅游经济 | 73篇 |
贸易经济 | 356篇 |
农业经济 | 173篇 |
经济概况 | 286篇 |
水利工程 | 6417篇 |
出版年
2024年 | 42篇 |
2023年 | 131篇 |
2022年 | 155篇 |
2021年 | 220篇 |
2020年 | 249篇 |
2019年 | 264篇 |
2018年 | 275篇 |
2017年 | 306篇 |
2016年 | 347篇 |
2015年 | 366篇 |
2014年 | 425篇 |
2013年 | 446篇 |
2012年 | 577篇 |
2011年 | 606篇 |
2010年 | 473篇 |
2009年 | 469篇 |
2008年 | 518篇 |
2007年 | 524篇 |
2006年 | 445篇 |
2005年 | 401篇 |
2004年 | 333篇 |
2003年 | 336篇 |
2002年 | 255篇 |
2001年 | 202篇 |
2000年 | 167篇 |
1999年 | 174篇 |
1998年 | 146篇 |
1997年 | 110篇 |
1996年 | 123篇 |
1995年 | 109篇 |
1994年 | 115篇 |
1993年 | 74篇 |
1992年 | 58篇 |
1991年 | 32篇 |
1990年 | 29篇 |
1989年 | 23篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1981年 | 1篇 |
排序方式: 共有9540条查询结果,搜索用时 421 毫秒
1.
2.
Self-service technologies (SSTs) increasingly permeate retail space. Yet, sometimes retailers decide to revert to human-delivered service mode by discontinuing their incumbent SST. In this study, we examine how self-checkout (SCO) discontinuance affects customers’ perceptions of SCO technology and purchase behavior. We conduct a natural field experiment by surveying two groups of customers pre- and post- SCO discontinuance: treatment group (who experience discontinuance) and control group (who do not experience discontinuance). Leveraging difference-in-differences analyses, we find that SCO discontinuance results in decreases in customers’ satisfaction with technology, intentions to use technology, perceived simplicity of technology, and basket size. Our results inform managers of the potential downsides of discontinuing SST and provide corroborating evidence of the technology’s benefits. 相似文献
3.
While workplace resources are generally viewed as positively affecting performance, some studies indicate that not all resources increase performance. This study addresses the controversial disparate effects of workplace resources on performance by exploring functionally classified workplace resources in self-managing service teams and their relative impacts on team service quality. Considering membership dynamics and consequences between members, a field experiment was conducted in a cafeteria, with data collected through a working diary for workplace resources and a customer survey to evaluate service quality. Results suggest that efficacy-resources in self-managing teams should be controlled with caution as they may adversely affect team service quality. Supporting the person–situation interactionism perspective, workplace resources interact dynamically with individual employees and with situations. Esteem-resources were found to increase team service quality, while team-member exchange not only improved team service quality but also moderated the impact of esteem-resources on team service quality. 相似文献
4.
葛洲坝水利枢纽泄水建筑物进水口冲磨与修复 总被引:2,自引:1,他引:1
葛洲坝水利枢纽工程已运行20余年,近年水下检查中发现泄水建筑物进水口存在不同程度的冲磨,有些已威胁到建筑物安全运行,分析冲磨原因和探讨修复材料和手段是非常重要的,本文就此问题提出一些看法和建议供参考。 相似文献
5.
通过物理模型试验,研究了有植被的河道水流紊动特性.试验结果表明,在复式断面河道滩地种植柔性植被后,滩地糙率增大,水流紊动更为剧烈,河道水流紊动强度峰值由原先的滩槽交界区转移到滩地区.滩地的水流紊动强度沿程递减;滩槽交界区的水流紊动强度沿程不断增大;主槽的水流紊动强度主要与床面糙率有关,滩地植被影响了滩地水流的归槽时间,使主槽水流流速沿程增大. 相似文献
6.
7.
为了提高非稳定渗流计算的计算精度 ,通过数学分析得到了水位传导系数随时间变化时 ,一类非稳定渗流井流模型的半解析解 ,并进行了计算比较 相似文献
8.
供应链核心在于实现供应链环节中的信息沟通,数据互换和协同工作,改造和整合企业的业务流程,因此供应链系统模型应该具有动态可重构的特点,系统主体的构成也应反映这种思想,在系统中引入“大规模定制”,“工作流”的新思想和“异构系统兼容”,“通用报表”以及“三层架构应用体系及开发手段”等新技术将使供应链系统更为“敏捷”。 相似文献
9.
介绍了堆石料与基岩面的现场直剪试验方法,6个组次的直剪试验结果表明,堆石料与基岩面的抗剪强度指标随基岩面坚硬度的增大而增加,并随基岩面粗糙度的加大而加大。 相似文献
10.
An approach is presented to satisfy the demand for simple criteria, guidelines and models for the preliminary sizing of horizontal subsurface flow (SF) constructed wetland systems. This approach eliminates time-consuming calculations and iterations by providing graphical solutions for wetland system sizing. Therefore, it can be used for the preliminary assessment of new or performance evaluation of existing subsurface flow constructed wetland systems. The validity of this methodology is checked with data from existing systems and is found to be quite satisfactory. This methodology is combined with simple equations predicting the maximum wetland capacity in summer, so as to assist designers in sizing installations in tourist areas with increased summer populations. Furthermore, based on this methodology, a sensitivity analysis is performed of the area requirements for wastewaters of various strengths and various design conditions and performance criteria. The results provide a useful overview to engineers and further simplify the design methodology of new subsurface flow constructed wetland systems. 相似文献