全文获取类型
收费全文 | 669篇 |
免费 | 23篇 |
专业分类
公路运输 | 75篇 |
综合类 | 343篇 |
水路运输 | 164篇 |
铁路运输 | 56篇 |
综合运输 | 54篇 |
出版年
2023年 | 5篇 |
2022年 | 12篇 |
2021年 | 19篇 |
2020年 | 21篇 |
2019年 | 13篇 |
2018年 | 7篇 |
2017年 | 16篇 |
2016年 | 20篇 |
2015年 | 21篇 |
2014年 | 50篇 |
2013年 | 45篇 |
2012年 | 66篇 |
2011年 | 55篇 |
2010年 | 39篇 |
2009年 | 39篇 |
2008年 | 36篇 |
2007年 | 57篇 |
2006年 | 46篇 |
2005年 | 28篇 |
2004年 | 23篇 |
2003年 | 17篇 |
2002年 | 12篇 |
2001年 | 13篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有692条查询结果,搜索用时 31 毫秒
1.
ABSTRACT This paper explores the online channel strategies adopted by Chinese manufacturers with regard to the Belt and Road. It also investigates the effect of offline channel power structures and maritime transportation costs on online channel mode selection and pricing strategies. The offline channel power structures are classified into three types, namely, Chinese manufacturer Stackelberg (MS) structure, vertical Nash (VN) structure, and foreign retailer Stackelberg (RS) structure. Furthermore, a game model is developed among the Chinese manufacturer, foreign retailer, and cross-border e-tailer to investigate the interactions among offline channel power structures, maritime transportation costs, and Chinese manufacturers’ online channel mode selection. The results show that Chinese manufacturers’ preferences for the online agency selling mode increases correspondingly with the decrease in their market position and bargaining power. Moreover, foreign retailers can obtain higher profits in the online agency selling mode under the VN structure. However, the level of profit for foreign retailers depends on the intensity of their competition with cross-border e-tailers under the MS and RS structures. Finally, consumers in countries along the Belt and Road can obtain a higher surplus in the online agency selling mode under all of the structures. 相似文献
2.
采用多聚酶链反应(PCR)技术,以Y染色体特异重复序列Y1.1、Y1.2和SRY基因编码区P1、P2为引物,分析了用孕妇外周血进行胎儿性别诊断的可靠性,并与绒毛样本进行了对比。结果表明:用孕妇外周血时,Y1.1,Y1.2引物的诊断符合率为75%;P1、P2引物不能扩增出Y特异DNA序列。而用绒毛样本时,两种引物的诊断符合率均为100%。结果提示:孕妇外周血PCR技术用于胎儿性别诊断尚有待改进,而采用绒毛样本进行胎儿性别诊断更为可靠。 相似文献
3.
在散粮皮带传送装置中,JC3驱动链轮的正常运行非常重要。由于其体积和重量较大,这给维修带来了不小的难度。本篇文章主要是介绍该大型链轮在链轮互换思想指导下所进行的维修技术和方法。 相似文献
4.
基于马尔可夫链的极值波高预测 总被引:1,自引:0,他引:1
本文研究了由日最大波高系列估算设计极值波高时,相邻日最大波高间的相关性对极值预测的影响,从日最大波高系列遵从马尔可夫链的假定出发,考虑到国内外经常采用对数一正态分布的韦布尔分布拟合波高长期分布的现实,本文用解析法求解了对数一正态分布情况下的极值预测。同时,对解析法难以求解的非正态随机变量情况(如韦布尔分布),用计算机随机模拟方法求解其极值预测,用上述两种方法对北大西洋和北海有关日最大波高系列的预测 相似文献
5.
6.
在企业的生产、管理过程中,如何提高订单执行力的研究仍是一个空白。此文针对当前制造业生产环境存在的主要问题,即生产面临复杂的环境、市场变化的不确定性导致激烈的市场竞争、订单执行过程的协调性较差,进行分析与探讨,提出提高企业订单执行力的方法和可采取的4个方面的措施,从而建立起一套在供需链管理模式下的高效订单执行力体系,使企业快速拓展市场,实现增值和稳步发展。 相似文献
7.
8.
Assessing sustainability of supply chains is a critical and increasingly complex problem. In recent years sustainability has received more attention in supply chain management (SCM) literature with triple bottom lines including social, environmental, and economic factors. Conventional data envelopment analysis (DEA) models consider decision making units (DMUs) as black boxes that consume a set of inputs to produce a set of outputs and do not take into consideration internal interactions of DMUs. Two-stage DEA models deal with such DMUs. However, existing two-stage DEA models are applicable only in technologies characterized by positive inputs/outputs. This paper aims to build and present a new two-stage DEA model considering negative input-intermediate-output data. Some numerical examples along with some theorems and properties are given to show capability of proposed method. The proposed ideas are used in a case study where 29 Iranian supply chains producing equipment of expendable medical devices are evaluated in terms of sustainability. 相似文献
9.
The management of products’ end-of-life and the recovery of used products has gained significant importance in recent years. In this paper, we address the carbon footprint-based problem that arises in a closed-loop supply chain where returned products are collected from customers. These returned products can either be disposed of or be remanufactured to be resold as new ones. Given this environment, an optimization model for a closed-loop supply chain (CLSC) in which carbon emission is expressed in terms of environmental constraints, i.e., carbon emission constraints, is developed. These constraints aim to limit the carbon emission per unit of product supplied with different transportation modes. Here, we design a closed-loop network where capacity limits, single-item management and uncertainty on product demands and returns are considered. First, fuzzy mathematical programming is introduced for uncertain modeling. Then, the statistical approach to the possibility to synthesize fuzzy information is utilized. Therefore, using a defined possibilistic mean and variance, we transform the proposed fuzzy mathematical model into a crisp form to facilitate efficient computation and analysis. Finally, the risk caused by violating the estimated resource constraints is analyzed so that decision makers (DMs) can trade off between the expected cost savings and the expected risk. We utilize data from a company located in Iran. 相似文献
10.
连锁经营管理专业人才培养目标大多定位在一线服务员或基层管理者,所培养的学生必须具备较强的连锁专业能力和创业能力,而大多数高职院校培养出来的学生在这些方面所表现出来的能力却差强人意,尤其是创业能力方面。本文提出将加盟创业项目贯穿于连锁经营管理实践教学全过程,按照“仿真训练-校内孵化-校内模拟-市场全真”四个阶段,形成一个递进式的实践教学流程,从而促使学生的专业能力和创业能力实现递进式提升。 相似文献