全文获取类型
收费全文 | 3726篇 |
免费 | 383篇 |
国内免费 | 442篇 |
专业分类
财政金融 | 13篇 |
工业经济 | 30篇 |
计划管理 | 411篇 |
经济学 | 92篇 |
综合类 | 40篇 |
运输经济 | 386篇 |
旅游经济 | 36篇 |
贸易经济 | 87篇 |
农业经济 | 22篇 |
经济概况 | 64篇 |
水利工程 | 3370篇 |
出版年
2024年 | 14篇 |
2023年 | 38篇 |
2022年 | 65篇 |
2021年 | 94篇 |
2020年 | 100篇 |
2019年 | 98篇 |
2018年 | 120篇 |
2017年 | 170篇 |
2016年 | 173篇 |
2015年 | 174篇 |
2014年 | 213篇 |
2013年 | 182篇 |
2012年 | 258篇 |
2011年 | 305篇 |
2010年 | 204篇 |
2009年 | 207篇 |
2008年 | 231篇 |
2007年 | 239篇 |
2006年 | 211篇 |
2005年 | 190篇 |
2004年 | 201篇 |
2003年 | 158篇 |
2002年 | 134篇 |
2001年 | 107篇 |
2000年 | 98篇 |
1999年 | 99篇 |
1998年 | 73篇 |
1997年 | 90篇 |
1996年 | 77篇 |
1995年 | 66篇 |
1994年 | 41篇 |
1993年 | 32篇 |
1992年 | 33篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 15篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 4篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 9篇 |
1979年 | 1篇 |
排序方式: 共有4551条查询结果,搜索用时 0 毫秒
61.
ABSTRACTThe purposes of this article are to depict ongoing trends regarding the transport system in Europe, to introduce readers to the challenges that Europe (and the rest of the world) will face in the future, to show which strategies Europe plans to deploy to mitigate the negative impacts the transport system imposes on the overall system, and finally to discuss the potential of these suggested strategies to contribute to the objectives of the European Union in the long run. 相似文献
62.
With rising interest in and concern about climate change and environmental sustainability, and the significance of the tourism industry worldwide, the impact of tourism-related activities and behaviors on the environment has become a key area of research. In particular, transport related to tourism has come under scrutiny for its contribution to the ecological footprint of tourism of a destination, mostly accounted for by the dominance of air travel. This study contributes to research in this area by identifying the types of travel situations in which tourists make environmentally friendly choices about travel modes and, consequently, which types of tourism destinations should seek to develop and promote in order to minimize the environmental impact of the tourist sector on both an individual destination and global scale. 相似文献
63.
Davina Joanne Stanford 《Journal of Sustainable Tourism》2014,22(4):666-683
This research uses a market segmentation approach to reducing transport-related environmental burdens from visitors, while maintaining economic benefit. The approach was tested in the Lake District National Park (UK). It aimed first to explore visitor transport behaviour using a social psychological framework, to understand what might best predict desired behaviour change (i.e. reduced visitor car use). Second, it developed and tested different types of marketing messages to reduce car use, based on persuasive communication theory, establishing marketing propositions appropriate to different visitor types and market segments. Third, it identified market segments with both a high propensity towards positive behavioural change and the highest economic contribution to the destination. The work is based on Ajzen's Theory of Planned Behaviour and on persuasive communication. Three hundred and ninety completed questionnaires were obtained. The paper emphasises the importance of context in successful communication to influence behaviour and shows that a market segmentation approach to behavioural change can be successful. Complex patterns of visitor mobility and modal choice emerge. For example “New Explorers” and “Familiar Families” are most likely to reduce their car use (45% and 48% respectively) and less likely to perceive this as difficult. 相似文献
64.
The river reach is a pervasive term within contemporary river research and applications. Yet, despite its prevalence, there is a notable lack of consistency in its definition. This paper identifies the presence of two broad types of reach definition within the academic literature, operational and functional, and argues that a functional definition is more suitable for applications within river research and management. A range of sequence zonation algorithms that were originally derived for geological well‐log analysis were compared for their ability to automatically identify functional reach boundaries. An analysis of variance‐based global boundary hunting algorithm was identified as the most suitable. To demonstrate the potential practical applications of automatic reach delineation methods, two case studies where functional reach boundaries have been identified were described: first, in a sequence of predicted sediment transport capacities for use in a reach‐based sediment transport model; and second, in a sequence of RHS Habitat Quality Assessment scores for identification of lengths of channel in need of habitat restoration efforts. Finally, the paper discusses how this type of functional reach identification procedure might be applied in other areas of river research and applications and how a multivariate version of a statistical zonation algorithm might prove useful in facilitating integrated catchment management by identifying reach boundaries common across all variables of interest in the system. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
65.
水石流的输沙浓度与流动速度 总被引:1,自引:0,他引:1
自然界水石流以粗颗粒为主体 ,仍有一部分作悬移运动的细颗粒存在 ,这种情况下 ,水石流输沙浓度不仅与沟道纵坡有关 ,还与细颗粒含量有关。研究表明 ,水石流中细颗粒的存在 ,其输沙浓度比相同纵坡下没有细颗粒时有很大提高。由于水石流中细颗粒所占比重小 ,故其液相流速可以通过对一般水流流速公式的阻力因子进行修正获得。水石流的流速随其浓度增加而减少 ,在相同浓度下 ,水石流流速还因细颗粒含量大小而变化 ,在浓度较低时 (Sv <0 4 5 )影响还不明显 ,在浓度较高时 (Sv>0 4 5 ) ,细颗粒含量增加 ,使同浓度水石流的流动速度提高。笔者求得的水石流流速公式 ,经实际观测资料检验 ,结果满意 相似文献
66.
This paper, Part I in a series of two, develops a mathematical model for earthern dam breach erosion. This model constitutes an extension of the Breach Erosion of Earthfill Dams (BEED) model developed by Singh and Scarlatos (1987). Two aspects are emphasized: the evolution of the dam breach, and the subsequent flood and sediment routing. Simulation of dam breach evolution is based on hydrologic, geometric and geotechnic considerations. Einstein-Brown and Bagnold equations are utilized to compute the rate of erosion in the breached section. A water routing scheme, based on a modified version of the Muskingum method to simulate flow exchange between channel and floodplains, is used to route the resulting breach hydrograph. A sediment routing scheme based on the Muskingum method, modified to simulate deposition in floodplains, and deposition and scouring in the channel, is utilized to route the breach sediment graph. In Part II, the model is tested against historical dam failures, and an analysis is made to determine its sensitivity to various parameters. 相似文献
67.
Milagros Fernández-Herrero Óscar González-Benito 《Asia Pacific Journal of Tourism Research》2019,24(7):658-668
Noting increasingly independent traveling by tourists, as well as changes on the tourist activity worldwide due to the 2008 economic crisis, this study analyzes the relationships between an economic crisis, tourist’s self-organization in trip planning, and tourist’s trip satisfaction. Data from a panel (2006–2011) on how residents in Spain complete their accommodation and transport bookings are used, including data on their trip satisfaction. The study identifies a negative relationship between the 2008 economic crisis and trip satisfaction, a positive relationship between self-organization and satisfaction, as well as positive moderating effects of the crisis on the relationship between self-organization and satisfaction. 相似文献
68.
K. G. Wilkinson 《Tourism Management》1982,3(4):291-293
The past half-century of developments in air transport are assessed and the current state of air technology and the economics of air transport assessed, particularly the trends since the 1973 ‘oil crisis’. The role of government in the industry in viewed as critical for its future health. 相似文献
69.
Werner Gronau 《Journal of Sustainable Tourism》2017,25(2):265-275
Constantly growing transport demand by tourists within holiday destinations and related increases in CO2 emissions have helped foster a new trend amongst German destinations towards promoting a green transportation mode for vacationers. A key innovation is the “Gästeticket” or Guest Ticket concept, which offers tourists free public transport, on buses and trains, within defined destination areas throughout their stay. This paper describes the background to this concept, and the many different ways in which it has been created, designed, implemented and administered. A qualitative research methodology interviewed key public and private sector stakeholders, including local and regional politicians, accommodation providers, public transport providers and public transport authorities to identify favourable starting conditions, successful financial and institutional implementation strategies, and both supporters and opponents of guest tickets. Local politicians and many small accommodation providers opposed the concept, while regional and national politicians supported it, as did public transport providers and public transport authorities. The concept is compared to the more holistic Alpine Pearls concept founded in Austria, and the case made for better explanation of the Guest Ticket concept to its opponents, better marketing, further research and closer cooperation between transport providers and planners with tourism attractions and accommodation providers. 相似文献
70.
结合铁路运输企业成本管理现状,探讨铁路运输企业实施成本领先战略的具体做法,借助价值链工具对铁路运输企业生产经营活动进行分析。 相似文献