全文获取类型
收费全文 | 2588篇 |
免费 | 174篇 |
国内免费 | 68篇 |
专业分类
安全科学 | 137篇 |
废物处理 | 27篇 |
环保管理 | 1179篇 |
综合类 | 687篇 |
基础理论 | 434篇 |
环境理论 | 2篇 |
污染及防治 | 57篇 |
评价与监测 | 65篇 |
社会与环境 | 148篇 |
灾害及防治 | 94篇 |
出版年
2023年 | 20篇 |
2022年 | 40篇 |
2021年 | 50篇 |
2020年 | 56篇 |
2019年 | 51篇 |
2018年 | 62篇 |
2017年 | 92篇 |
2016年 | 100篇 |
2015年 | 102篇 |
2014年 | 99篇 |
2013年 | 138篇 |
2012年 | 91篇 |
2011年 | 154篇 |
2010年 | 101篇 |
2009年 | 128篇 |
2008年 | 120篇 |
2007年 | 133篇 |
2006年 | 122篇 |
2005年 | 100篇 |
2004年 | 85篇 |
2003年 | 90篇 |
2002年 | 65篇 |
2001年 | 69篇 |
2000年 | 67篇 |
1999年 | 77篇 |
1998年 | 49篇 |
1997年 | 46篇 |
1996年 | 49篇 |
1995年 | 45篇 |
1994年 | 30篇 |
1993年 | 21篇 |
1992年 | 24篇 |
1991年 | 21篇 |
1990年 | 13篇 |
1989年 | 14篇 |
1988年 | 15篇 |
1987年 | 24篇 |
1986年 | 25篇 |
1985年 | 27篇 |
1984年 | 25篇 |
1983年 | 16篇 |
1982年 | 17篇 |
1980年 | 17篇 |
1979年 | 19篇 |
1978年 | 22篇 |
1977年 | 15篇 |
1975年 | 10篇 |
1973年 | 16篇 |
1972年 | 14篇 |
1971年 | 16篇 |
排序方式: 共有2830条查询结果,搜索用时 906 毫秒
981.
Spiros M. Karakostas 《Journal of Land Use Science》2016,11(5):595-617
The successful implementation of major development initiatives relies on the sound allocation of land uses against critical design criteria and constraints. The discovery of optimum development plans introduces severe complexities in formulating and solving the underlying multi-objective optimization problem. Moreover, in the presence of conflicting planning criteria decision-makers should be provided with a set of alterative-yet-optimum solutions that uniformly cover the spectrum of feasible maps. The introduction of sophisticated optimization algorithms addresses this challenge by pursuing a complete approximation of the Pareto front containing all prominent spatial allocations. This study demonstrates the effectiveness of a new evolutionary algorithm (UDT-MOEA) against the results of an established multi-objective genetic algorithm (NSGA-II) when applied on a major greenfield initiative against the optimum location(s), size and shape of three new land uses. Each algorithm performs best in different areas of the feasible objective space, providing planning alternatives with distinct characteristics. 相似文献
982.
An interval joint-probabilistic programming method for solid waste management: a case study for the city of Tianjin, China 总被引:1,自引:0,他引:1
Yi XU Shunze WU Hongkuan ZANG Guiguang HOU 《Frontiers of Environmental Science & Engineering》2014,8(2):239-255
Currently, environmental protection and resources conservation continue to be challenges faced by solid-waste managers in China. These challenges are being further compounded by rapid socioeconomic devel- opment and population growth associated with increased waste generation rates and decreased waste disposal capacities. In response to these challenges, an interval joint-probabilistic mixed-integer programming (IJMP) method is developed for supporting long-term planning of waste management activities in the city of Tianjin, which is one of the largest municipalities in the northern part of China. In the IJMP, joint probabilistic constraints are introduced into an interval-parameter mixed-integer programming framework, such that uncertainties presented in terms of interval values and random variables can be reflected. Moreover, a number of violation levels for the waste-management-capacity constraints are examined, which can facilitate in-depth analyses of tradeoffs among economic objective and system-failure risk. The results indicate that reasonable solutions have been generated. They are valuable for supporting the adjustment of the city's existing waste-management practices and the long- term planning of the city's waste-management facilities. 相似文献
983.
Mark Kammerbauer 《Disasters》2013,37(3):401-419
This paper examines a city and a natural disaster, specifically New Orleans, Louisiana, after Hurricane Katrina of August 2005. Recovery here is ongoing and the process of return is incomplete, with long‐term dislocation to other cities in the United States, such as Houston, Texas. The question arises as to how planning and stratification influence evacuation and return/dislocation and how they result in a particular practice of adaptation. This interrelated process is conceptually integrated and termed ‘schismo‐urbanism’ and is analysed within a multidimensional theoretical framework to evaluate aspects of urban sociology and natural disasters. Empirical research is based on a quantitative and qualitative mixed‐method case study. Data were collected during two rounds of field research in New Orleans and Houston in 2007 and 2009. As a comparative socio‐spatial study of affected and receptor communities, it makes a novel theoretical and methodological contribution to research on urban disasters in the context of continuing and rapid social change, and is targeted at disaster researchers, planning theorists and practitioners, and urbanists. 相似文献
984.
《Environmental Hazards》2013,12(3-4):291-310
This study uses multilevel regression analysis to examine the effect of social characteristics and the built environment on clearance time under an evacuation scenario. The primary unit of analysis is the US Census tract (N?=?1660), nested within 31 incorporated places spanning five US states. The dependent variable is an estimate of clearance time in hours derived using network analysis techniques within a geographic information system. We find that tracts with a more peripheral location, more female residents, a higher proportion of Hispanic residents, and higher median household incomes are associated with higher clearance times, on average. Our research suggests the relationship between suburbanization and clearance time is complex and evolving, mediated by past investments in the built environment and shifting social conditions. In addition to facilitating the evacuation of areas with low access to personal vehicles, urban planners and emergency management officials should also consider how the degree of connectivity in the street network impacts congestion and clearance time. 相似文献
985.
X. Wang 《国际发展与全球生态学杂志》2013,20(4):239-249
Based on the case study of Shenzhen Special Economic Zone, China, this paper investigates the theories and application of ecological planning for promoting urban sustainable development. The stated significance of such development is to promote the co-ordination of relationships between man and nature, and man and the environment. 相似文献
986.
H. Briassoulis 《国际发展与全球生态学杂志》2013,20(2):110-120
The central argument of the paper is that effective pollution prevention can be achieved only by integrated land-use planning which offers the broad framework for co-ordinating technological and non-technological means to achieve sustainable development. The paper first reviews the role of land-use in preventing or contributing to pollution over time, focusing especially on contemporary efforts to promote environmental protection through land-use planning and management. The relationship between land-use, pollution and sustainable development is analysed by examining the most important types of land-use-related problems, discussing their causes and identifying a number of land-use-related constraints to sustainable development. Finally, a land-use planning and policy framework approach to pollution prevention for sustainable development is outlined which emphasizes the need for integrated analysis of pollution problems and adoption of comprehensive approaches to their solution. Scientific, spatial, temporal and policy issues are addressed in the context of the proposed approach. 相似文献
987.
Because of the expanding population in our cities with its demands for more diversified services, we cannot afford a piecemeal type of urban underground growth. Utilization of the urban street system for buried utilities has a serious adverse effect on other street functions because of the continuing necessity to perform excavations for the repair of existing lines and the installation of new ones. The excavations not only are a serious cause of traffic delay and congestion but also create noise and aesthetic disturbances, and result in excessive street maintenance requirements and in shortened overall street life. Consider the enhancing effects in quietness on abutting properties and users of the street, and the benefits become very great. Unfortunately, the lack of data and the difficulty in quantifying the intangibles have made it impossible to arrive at a reasonably accurate figure of overall negative impact on the urban environment of street cuts. However, if drivers are sufficiently strong to merit the use of utility tunnels, then sustainable municipal policies improving living quality will be implemented. 相似文献
988.
ABSTRACTIn 1985, San Francisco adopted a wind comfort standard in its Downtown Area Plan in response to increasing concerns about the city’s downtown public open spaces becoming excessively windy. After 30 years of implementation, this study revisits the standard and examines its effectiveness in promoting pedestrian comfort. Seven hundred one valid samples were collected from 6 months of field study, which combined surveying pedestrians and on-site collection of microclimate data. Statistical analysis and an assessment using the physiological equivalent temperature show that 11 mph (4.92 m/s), the comfort criterion in places for walking, performs as an effective determinant of outdoor comfort in San Francisco. This study sheds light on climate-resilience of cities, as they have become key urban challenges today. 相似文献
989.
In this paper, I show the existence and the characteristics of equilibrium in a non-renewable resource market where extraction costs are non-convex and market price is subject to stochastic shocks, an empirically relevant setting. In my model firms may be motivated to hold inventories to facilitate production smoothing, which allows them to continue producing at a smooth pace at any instant when extraction ceases, e.g. when reserves are exhausted. This aspect of the model then supports a competitive equilibrium in the presence of non-convex costs. Casual empirical evidence is provided that supports the central features of my model for a variety of non-renewable resources, lending credence to the explanation for equilibrium I propose. 相似文献
990.
非常规突发事件应急决策方法研究 总被引:2,自引:0,他引:2
为深入研究非常规突发事件应急决策方法,提高对非常规突发事件的应对能力,调查研究基于应急预案、范例推理和智能规划等3种非常规突发事件的应急决策方法,对比分析这3种方法的特点。研究发现:这3种方法都可以在一定程度上为非常规突发事件提供辅助决策,但是基于智能规划的应急决策方法更适于非常规突发事件复杂的决策环境,有较大发展潜力。然后针对该方法,提出一些需要深入研究的开放性课题。 相似文献