全文获取类型
收费全文 | 3012篇 |
免费 | 228篇 |
国内免费 | 568篇 |
专业分类
安全科学 | 324篇 |
废物处理 | 40篇 |
环保管理 | 342篇 |
综合类 | 1805篇 |
基础理论 | 416篇 |
环境理论 | 1篇 |
污染及防治 | 178篇 |
评价与监测 | 157篇 |
社会与环境 | 309篇 |
灾害及防治 | 236篇 |
出版年
2024年 | 10篇 |
2023年 | 51篇 |
2022年 | 94篇 |
2021年 | 95篇 |
2020年 | 89篇 |
2019年 | 80篇 |
2018年 | 108篇 |
2017年 | 114篇 |
2016年 | 135篇 |
2015年 | 127篇 |
2014年 | 138篇 |
2013年 | 195篇 |
2012年 | 174篇 |
2011年 | 233篇 |
2010年 | 165篇 |
2009年 | 174篇 |
2008年 | 110篇 |
2007年 | 203篇 |
2006年 | 208篇 |
2005年 | 172篇 |
2004年 | 134篇 |
2003年 | 171篇 |
2002年 | 127篇 |
2001年 | 115篇 |
2000年 | 98篇 |
1999年 | 82篇 |
1998年 | 73篇 |
1997年 | 53篇 |
1996年 | 49篇 |
1995年 | 50篇 |
1994年 | 40篇 |
1993年 | 33篇 |
1992年 | 37篇 |
1991年 | 18篇 |
1990年 | 14篇 |
1989年 | 4篇 |
1988年 | 16篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3808条查询结果,搜索用时 15 毫秒
921.
Women, Health and Humanitarian Aid in Conflict 总被引:4,自引:0,他引:4
The burden of political conflict on civilian populations has increased significantly over the last few decades. Increasingly, the provision of resources and services to these populations is coming under scrutiny; we highlight here the limited attention to gender in their provision. Women and men have different exposures to situations that affect health and access to health-care and have differential power to influence decisions regarding the provision of health services. We argue that the role of women in planning is central to the provision of effective, efficient and sensitive health-care to conflict-affected populations. 相似文献
922.
丁烷与空气混合物的爆炸性能测定 总被引:1,自引:0,他引:1
在不同条件下,对丁烷与空气混合物进行爆炸实验,由微机数采测试系统测定其爆炸参数(爆轰波压力、爆轰波传播速度等)、爆轰极限以及当其形成爆轰时所需的临界起爆能。通过实验测定,为评价丁烷与空气混合物的安全性能提供重要依据 相似文献
923.
中外大城市震灾管理模式的对比分析 总被引:2,自引:0,他引:2
对随机选取的8个发生在大城市的地震,分为发达国家和发展中国家两组,分别对其造成的死亡人数和经济损失以及震前准备、震后救援、致灾因素等管理措施进行了统计对比,并归纳出应该吸取的经验教训。 相似文献
924.
湖南省历史旱灾时空分布规律 总被引:8,自引:2,他引:8
本文综合考虑气候条件、下垫面条件、史料记载的均一性等因素,将湖南省划分为10个研究区;根据1450~1949年湖南省气候史料记载1),采用区内平均等级,描绘了全省10个区旱灾的时间序列,并据此探讨了全省近500a来旱灾的时空分布规律。 相似文献
925.
我国秦至清末的疫病灾害研究 总被引:4,自引:0,他引:4
本文根据《中国历代天灾人祸表》中疫病的文字记载,统计出各个历史时期疫病发生时间(季节)、频数及其与旱、涝(水)、地震、战争等灾难事件的关系,进而推测历史时期疫病所包含的急性传染病。统计发生周期,证实疫病周期与太阳、太阳系活动规律有明显的相关性。 相似文献
926.
城市地震灾害预测的基本内容和减灾决策过程 总被引:12,自引:1,他引:12
本文研究了下列四个问题:(1)对我国现有建筑进行了易损性分类,并定义了一个区分易损性类别的定量指标;(2)按目前现有建筑建立了各类易损性结构的震害矩阵和它们与未来若干年后的震害矩阵的关系;(3)分析并了种类易损性结构的地震损失率;(4)提出了一个人员死亡的估计方法和确定减灾方案的决策方法。 相似文献
927.
Vujica Yevjevich Nilgun Bayraktar Harmancioglu 《Journal of the American Water Resources Association》1985,21(4):625-633
ABSTRACT: water resources supply and demand time series consist of several or all of the four basic characteristics: tendency, intermittency, periodicity and stochasticity. Their importance changes from one type of variables to another. Historic developments of analysis of time series in hydrology have varied significantly over the past, from the stress on search for periodicities and persistence in annual series to the emphasis on the series stochastic properties. Supply and demand series are often highly interrelated, which fact is most often neglected in planning water resources systems in general, and water storage capacities in particular. The future of series analysis in water resources will likely be by a joint use of physically-based structural analysis and the use of advanced methods of treating data by stochastic processes, statistical estimation and inference techniques. The most intriguing challenge of the future of this analysis may be the treatment of nonnormal, nonlinear and in general nonstationary hydrologic and water use time series. The proper treatment of complex multivariate processes will also challenge the specialists, especially for the purposes of transfer of information between data on variables at given points, or between data at several points of a given variable, or both. 相似文献
928.
Avery H. Demond Paul V. Roberts 《Journal of the American Water Resources Association》1987,23(4):617-628
ABSTRACT: A key parameter in modeling two-phase flow phenomena is relative permeability. It is important to understand which variables influence relative permeability, especially since so few measurements of relative permeability have been made for typical contaminants at hazardous waste sites. This paper focuses on the effect of five variables on relative permeability: intrinsic permeability, pore-size distribution, viscosity ratio, interfacial tension, and wettability, by critically reviewing previously published relative permeability experiments. The wide variability in the functional relationship between relative permeability and saturation should be considered in attempts to model two-phase flow. 相似文献
929.
Methods development and use of macroinvertebrates as indicators of ecological conditions for streams in the Mid-Atlantic Highlands Region 总被引:2,自引:0,他引:2
Klemm DJ Blocksom KA Thoeny WT Fulk FA Herlihy AT Kaufmann PR Cormier SM 《Environmental monitoring and assessment》2002,78(2):169-212
The Mid-Atlantic Highlands Assessment (MAHA) included the sampling of macroinvertebrates from 424 wadeable stream sites to determine status and trends, biological conditions, and water quality in first through third order streams in the Mid-Atlantic Highlands Region (MAHR) of the United States in 1993–1995. We identified reference and impaired sites using water chemistry and habitat criteria and evaluated a set of candidate macroinvertebrate metrics using a stepwise process. This process examined several metric characteristics, including ability of metrics to discriminate reference and impaired sites, relative scope of impairment, correlations with chemical and habitat indicators of stream disturbance, redundancy with other metrics, and within-year variability. Metrics that performed well were compared with metrics currently being used by three states in the region: Pennsylvania, Virginia, and West Virginia. Some of the metrics used by these states did not perform well when evaluated using regional data, while other metrics used by all three states in some form, specifically number of taxa, number of EPT taxa, and Hilsenhoff Biotic Index, performed well overall. Reasons for discrepancies between state and regional evaluations of metrics are explored. We also provide a set of metrics that, when used in combination, may provide a useful assessment of stream conditions in the MAHR. 相似文献
930.