全文获取类型
收费全文 | 944篇 |
免费 | 63篇 |
国内免费 | 76篇 |
专业分类
安全科学 | 96篇 |
废物处理 | 18篇 |
环保管理 | 213篇 |
综合类 | 324篇 |
基础理论 | 165篇 |
污染及防治 | 43篇 |
评价与监测 | 17篇 |
社会与环境 | 145篇 |
灾害及防治 | 62篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 25篇 |
2021年 | 25篇 |
2020年 | 35篇 |
2019年 | 31篇 |
2018年 | 17篇 |
2017年 | 24篇 |
2016年 | 27篇 |
2015年 | 30篇 |
2014年 | 32篇 |
2013年 | 72篇 |
2012年 | 59篇 |
2011年 | 62篇 |
2010年 | 37篇 |
2009年 | 40篇 |
2008年 | 26篇 |
2007年 | 57篇 |
2006年 | 57篇 |
2005年 | 42篇 |
2004年 | 52篇 |
2003年 | 51篇 |
2002年 | 42篇 |
2001年 | 46篇 |
2000年 | 37篇 |
1999年 | 24篇 |
1998年 | 15篇 |
1997年 | 13篇 |
1996年 | 22篇 |
1995年 | 13篇 |
1994年 | 16篇 |
1993年 | 17篇 |
1992年 | 13篇 |
1991年 | 3篇 |
1990年 | 7篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
排序方式: 共有1083条查询结果,搜索用时 859 毫秒
301.
Emergency response is an important measure to reduce the loss of any major fire and prevent its escalation. There may be many fire trucks participating in the fire-fighting at the same time, and the scheduling of them will affect the fire-fighting efficiency and thus, capacity. This work focuses on the cycle process of fighting fire and refilling water of fire trucks, and analyzes and compares the scheduling strategies of the fire trucks. The simulation tool eM-plant is utilized to model the fire-fighting process. In view of the emergency response in relation to a chemical fire accident and to prevent its escalation, strategies in the analysis consider the allocation of fire trucks according to the distance of hydrants, the distribution of fire trucks according to the number of fire hydrants, etc. The results of this paper show that an even distribution of fire trucks leads to a good performance, but can be further adjusted to find a more optimal strategy. This study provides guidance for fire truck scheduling in case of emergency response. 相似文献
302.
综述了国外核事故应急监测策略研究进展,以及我国在核应急监测法规标准、应急监测方法、应急辐射环境监测技术等方面的研究现状,从海洋核动力平台的法规标准、应急监测方案、应急辐射监测项目和应急监测方法4个方面进行了探讨,并提出了制定核应急监测政策及标准规范、建立应急监测预案库、加快研发应急采样与监测方法、建立海洋放射性监测体系等建议。 相似文献
303.
我国石油需求预测及经济危机下的应对建议 总被引:2,自引:0,他引:2
石油资源的特殊性使得石油市场一直变幻莫测,尤其是当前经济危机影响下,我国石油市场的走向及应对策略成为了各界关注的焦点。石油需求的走向影响着我国石油政策的制定,因此石油需求的预测是很有意义的。本文应用灰色预测GM(1,1)模型,采用了1985至2008年这24年的石油需求数据,对我国未来五年的石油需求进行了预测,结果显示需求量将持续上升,而且增幅较为稳定。在此需求预测的基础上,结合我国目前石油市场的现状分析,认为存在的主要问题在于国内的石油供给不能满足日益增长的需求,导致石油消费对外依存度过高,能源安全存在隐患;另外,工业石油消耗强度过大也导致消费结构不合理,再加上我国石油进口多集中于中东等地区,渠道单一且不确定因素较多。结合当前经济危机条件的冲击影响,从保证国内石油供给、平衡能源消费结构和石油进口区域多元化这三方面提出了相关建议,认为应该加大国内外找油的步伐,多区域进口石油,并加大新能源和低能耗能源的研发,全面保障我国石油市场健康运行。 相似文献
304.
305.
本文详细分析了高职院校学生中非正式群体产生的心理原因、类型、特征和功能,提出了切实可行的教育对策. 相似文献
306.
青海省的主要灾害类型与防灾减灾对策 总被引:3,自引:2,他引:1
论述了青海地区常见的主要灾害类型及危害,并提出了防灾减灾的对策。 相似文献
307.
A geographic information system (GIS)-based approach with spatial analysis advantages was developed to optimize the total
emission control scheme on air pollution in Lanzhou, combined with Models-3 modeling system and a linear programming model.
GIS system is mainly used for establishing a multifactor assessment model to quantitatively divide environmental functional
zone, and also used for selecting control sites in linear programming model. The results show that most of the urban area
belongs to the second type of function, which is 122.8 km2 occupying about 76.5% and the third type of about 32.9 km2 occupying 20.5%. To reach the air quality up to the national standard in the entire control area, some large-emission factories
need to cut emissions from 19% to 27%. For small but low-emission height sources, the cut may be as high 40%. The improvement
of the ecological environment is urgently needed for controlling the background particle pollution in Lanzhou city. 相似文献
308.
309.
310.
Increased commercialisation of nanometal-based products augments the possibility of their deposition into aquatic ecosystems; this, in turn, may pose risks to aquatic biota and associated ecological functions. Freshwater invertebrate shredders mostly use microbially-colonized plant litter as food resource and play an important role in aquatic detritus food webs. We assessed lethal effects of nanoCuO on the shredder Allogamus ligonifer (Trichoptera, Limnephilidae) by determining the concentration that induced 50% of death (LC50), and sublethal effects of nanoCuO on the feeding behaviour and growth of the shredder by exposing the animals to: (i) stream water supplemented with nanoCuO and microbially-colonized leaves, and (ii) stream water (without nanoCuO) and microbially-colonized leaves pre-exposed to nanoCuO. Results from acute lethal tests showed that the 96 h LC50 of nanoCuO was very high (569 mg L−1). In the absence of nanoparticles, leaf consumption rate was 0.27 mg leaf DM mg−1 animal DM d−1 and the shredder growth rate was 56 μg animal DM mg−1 animal DM d−1. A significant inhibition in leaf consumption rate (up to 47%) and invertebrate growth rate (up to 46%) was observed when shredders were exposed to the higher tested sublethal concentration of nanoCuO (75 mg L−1) through either contaminated stream water or pre-contaminated food. The exposure to increased nanoCuO concentration via water or pre-contaminated food led to higher accumulation of copper in the larval body. Leached water-soluble ionic copper from the nanoCuO adsorbed or accumulated in the shredder (up to 10.2% of total Cu) seemed to influence the feeding behaviour and growth of the shredder. 相似文献