全文获取类型
收费全文 | 3397篇 |
免费 | 199篇 |
国内免费 | 1016篇 |
专业分类
安全科学 | 286篇 |
废物处理 | 196篇 |
环保管理 | 272篇 |
综合类 | 1901篇 |
基础理论 | 543篇 |
污染及防治 | 764篇 |
评价与监测 | 202篇 |
社会与环境 | 217篇 |
灾害及防治 | 231篇 |
出版年
2024年 | 9篇 |
2023年 | 58篇 |
2022年 | 189篇 |
2021年 | 148篇 |
2020年 | 135篇 |
2019年 | 121篇 |
2018年 | 171篇 |
2017年 | 150篇 |
2016年 | 136篇 |
2015年 | 192篇 |
2014年 | 286篇 |
2013年 | 288篇 |
2012年 | 271篇 |
2011年 | 266篇 |
2010年 | 222篇 |
2009年 | 214篇 |
2008年 | 198篇 |
2007年 | 201篇 |
2006年 | 159篇 |
2005年 | 105篇 |
2004年 | 122篇 |
2003年 | 128篇 |
2002年 | 149篇 |
2001年 | 146篇 |
2000年 | 113篇 |
1999年 | 97篇 |
1998年 | 64篇 |
1997年 | 48篇 |
1996年 | 53篇 |
1995年 | 44篇 |
1994年 | 26篇 |
1993年 | 19篇 |
1992年 | 12篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1969年 | 2篇 |
1963年 | 3篇 |
1961年 | 2篇 |
1958年 | 4篇 |
1930年 | 1篇 |
排序方式: 共有4612条查询结果,搜索用时 484 毫秒
711.
以可持续发展相关理论为基础,利用系统工程的理论和方法建立了河北省县域可持续发展指标体系及其评价标准,并在全省范围应用,对全省136个县(市)可持续发展能力做出了评价。结合评价结果,阐述了河北省县域可持续发展能力的特征,提出了河北省县域可持续发展的方向和思路。 相似文献
712.
713.
Jiansu Mao Yanchun Du Linyu Xu Yong Zeng 《Frontiers of Environmental Science & Engineering》2011,5(4):585-596
Improving eco-efficiency is propitious for saving resources and reducing emissions, and has become a popular route to sustainable development. We define two energy-related eco-efficiencies: energy efficiency (ENE) and greenhouse gas (GHG) emission-related eco-efficiency (GEE) using energy consumption and the associated GHG emissions as the environmental impacts. Using statistical data, we analyze China??s energy consumption and GHG emissions by industrial subsystem and sector, and estimate the ENE and GEE values for China in 2007 as 4.871×107 US$/PJ and 4.26×108 US$/TgCO2eq, respectively. Industry is the primary contributing subsystem of China??s economy, contributing 45.2% to the total economic production, using 79.6% of the energy consumed, and generating 91.4% of the total GHG emissions. We distinguish the individual contributions of the 39 industrial sectors to the national economy, overall energy consumption, and GHG emissions, and estimate their energyrelated eco-efficiencies. The results show that although ferrous metal production contributes only 3.5% to the national industrial economy, it consumes the most industrial energy (20% of total), contributes 16% to the total industrial global warming potential (GWP), and ranks third in GHG emissions. The power and heat sector ranks first in GHG emissions and contributes one-third of the total industrial GWP, although it only consumes about 8% of total industrial energy and, like ferrous metal production, contributes 3.5% to the national economy. The ENE of the ferrous metal and power and heat sectors are only 8 and 2.1×107 US$/PJ, while the GEE for these two sectors are 9 and 4×104 US$/GgCO2eq, respectively; these are nearly the lowest ENE and GEE values among all 39 industry sectors. Finally, we discuss the possibility of ecoefficiency improvement through a comparison with other countries. 相似文献
714.
Assessment of spatial distribution of soil loss over the upper basin of Miyun reservoir in China based on RS and GIS techniques 总被引:2,自引:0,他引:2
Chen T Niu RQ Wang Y Li PX Zhang LP Du B 《Environmental monitoring and assessment》2011,179(1-4):605-617
Soil conservation planning often requires estimates of the spatial distribution of soil erosion at a catchment or regional scale. This paper applied the Revised Universal Soil Loss Equation (RUSLE) to investigate the spatial distribution of annual soil loss over the upper basin of Miyun reservoir in China. Among the soil erosion factors, which are rainfall erosivity (R), soil erodibility (K), slope length (L), slope steepness (S), vegetation cover (C), and support practice factor (P), the vegetative cover or C factor, which represents the effects of vegetation canopy and ground covers in reducing soil loss, has been one of the most difficult to estimate over broad geographic areas. In this paper, the C factor was estimated based on back propagation neural network and the results were compared with the values measured in the field. The correlation coefficient (r) obtained was 0.929. Then the C factor and the other factors were used as the input to RUSLE model. By integrating the six factor maps in geographical information system (GIS) through pixel-based computing, the spatial distribution of soil loss over the upper basin of Miyun reservoir was obtained. The results showed that the annual average soil loss for the upper basin of Miyun reservoir was 9.86 t ha(-1) ya(-1) in 2005, and the area of 46.61 km(2) (0.3%) experiences extremely severe erosion risk, which needs suitable conservation measures to be adopted on a priority basis. The spatial distribution of erosion risk classes was 66.9% very low, 21.89% low, 6.18% moderate, 2.89% severe, and 1.84% very severe. Thus, by using RUSLE in a GIS environment, the spatial distribution of water erosion can be obtained and the regions which susceptible to water erosion and need immediate soil conservation planning and application over the upper watershed of Miyun reservoir in China can be identified. 相似文献
715.
716.
717.
中国民航维修系统正在建立安全管理体系,本文介绍了风险管理目的、构建原则并举例说明风险管理的实施步骤。为中国民航维修系统建立风险管理进行了有益的探索。 相似文献
718.
为推进我国核电产业技术水平的整体跨越,实现我国第三代核电AP1000的自主化过程中的安全,国家核电技术公司(以下简称“国家核电”)在建造过程中通过加强从业人员安全培训、企业安全文化建设和依托项目的安全管理,大力提升人的本质安全化水平;广泛采用新技术、改进施工工艺,实行模块化、专业化施工,加大安全基础设施投入力度,强化建造过程中的安全控制,努力打造核电建造过程中物的本质安全;完善安全管理制度,建设安全责任体系和监督体系,持续提高管理上的本质安全。 相似文献
719.
720.
战场噪声是造成单兵听力损伤的重要原因,通常要求单兵处于大于85dBA的噪声环境中需佩戴听力保护装置。听力保护装置通常包括耳罩式和耳塞式。新型单兵用耳塞式听力保护装置具有听力保护、环境声音的监听、持续及脉冲噪声抑制、通信接入等多种功能。 相似文献