首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   11524篇
  免费   916篇
  国内免费   1259篇
安全科学   2368篇
废物处理   161篇
环保管理   1717篇
综合类   4998篇
基础理论   877篇
污染及防治   666篇
评价与监测   1744篇
社会与环境   632篇
灾害及防治   536篇
  2024年   32篇
  2023年   173篇
  2022年   323篇
  2021年   360篇
  2020年   435篇
  2019年   310篇
  2018年   245篇
  2017年   381篇
  2016年   468篇
  2015年   474篇
  2014年   551篇
  2013年   680篇
  2012年   859篇
  2011年   880篇
  2010年   664篇
  2009年   701篇
  2008年   485篇
  2007年   744篇
  2006年   708篇
  2005年   623篇
  2004年   522篇
  2003年   542篇
  2002年   432篇
  2001年   317篇
  2000年   332篇
  1999年   274篇
  1998年   188篇
  1997年   203篇
  1996年   145篇
  1995年   151篇
  1994年   128篇
  1993年   96篇
  1992年   74篇
  1991年   43篇
  1990年   29篇
  1989年   25篇
  1988年   16篇
  1987年   11篇
  1986年   7篇
  1985年   6篇
  1984年   4篇
  1983年   3篇
  1982年   8篇
  1980年   9篇
  1979年   7篇
  1978年   8篇
  1977年   4篇
  1976年   3篇
  1972年   4篇
  1971年   4篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
针对工业和医用放射性同位素与射线装置发生放射性污染的安全隐患,采用PLC控制技术,设计一套联锁系统,有效地保护操作人员和公众,避免因为人为失误或设备故障造成放射性污染事故。  相似文献   
982.
The water disinfecting behavior of silver-modified clinoptilolite–heulandite rich tuff (ZSAg) as an antibacterial agent against coliform microorganisms from water in a continuous mode was investigated. Silver recovery from the disinfected effluents by the sodium-modified clinoptilolite–heulandite rich tuff (ZSNa) was also considered. Escherichia coli (ATCC 8739) and total coliform microorganisms, as indicators of microbiological contamination of water, were chosen to achieve the disinfection of synthetic wastewater or municipal wastewater. Ammonium (NH4+) and chloride (Cl) ions were added to the synthetic wastewater as an interfering chemical species on the disinfection processes. The antibacterial activity of the ZSAg as a bactericide was measured by the coliform concentration as evaluated by the APHA method. The amount of silver in the disinfected effluents was determined using atomic absorption spectroscopy. The inactivation of the ZSAg was calculated from the breakthrough curves based on the model reported by Gupta et al. It was found that when the silver concentration in the effluent is less than 0.6 μg/mL, the bacterial survival percentage increased and the volume of disinfected water diminished. The total silver amounts found in the effluent at the end of the disinfection processes varied depending on the water treated (synthetic or municipal wastewater). The presence of NH4+ ions in synthetic wastewater influent notably improved the disinfected water volume (zero NVC/100 mL), in comparison to the disinfection of the same influent without NH4+ ions. A contrary water disinfection behavior was observed in the presence of Cl ions. The silver recovery does not depend on the mass of the sodium zeolitic bed according with the wastewater to be treated (synthetic or municipal wastewater) and the presence of NH4+ or Cl ions in the influent also influenced the silver recovery from wastewater. The ZSNa did not have antibacterial activity. Therefore the amount of bactericide agent (silver-modified natural zeolite), coliform microorganisms from water (E. coli or consort of coliform microorganisms) as well as the water quality (synthetic wastewater or municipal wastewater) influenced both the disinfection process and the silver recovery in a column system.  相似文献   
983.
The authors present the beginnings of a planning support system (PSS) for agri-environmental measures exemplified by a virtual implementation of Colorfields and blooming strips on model farms, based on real-world data. This paper starts with an introduction to the Colorfields, a concept for transdisciplinary and sustainable landscape design of set-aside land. Colorfields comprise of blooming strips of flowering annual or biennial plants, which are designed and drilled in pattern on fallow land creating Land Art. The temporary scenic arrangements of the Colorfields combine the advantages of ecological strips, e.g. providing habitats for insects (especially bees), improving soil fertility through the cultivation of intercrops, with improvements of the social recognition of farmers as producers of pleasant landscapes instead of monoculture fields.The prototype of the PSS uses two software tools of different scientific origin, the bio-economic modeling system MODAM and the landscape visualization system Lenné3D, which are linked based on geo-data. The resulting system helps to assess the economic effects and visualizes the effects of the specific landuse patterns under different scenarios.The economic assessment of blooming strips on arable land and of one Colorfield on fallow land shows that these measures prove to be profitable from an economic viewpoint assuming the current area payments for the obligatory European Union set-aside program. Furthermore, the visualizations enable the design to be tested virtually by exploring the resultant scenery. They provide artists, planners and stakeholders including farmers with a tool to virtually wander through landscape scenarios supporting a collaborative design and a shared vision for the community.The results of the two model farms and previous case studies for Colorfields demonstrate how current policy conditions could be used for the improvement of environmental and scenic qualities. Furthermore, the ability of the tools, MODAM and Lenné3D, suggests to support and promote these activities.  相似文献   
984.
农村生活污水治理措施   总被引:1,自引:0,他引:1  
蒋克彬  彭松  王明明 《四川环境》2008,27(5):114-117
介绍了适合于国内农村生活污水治理的一些技术与措施。沼气技术是当前处理农村生活污水的较佳选择。  相似文献   
985.
文章分析了西北地区目前水资源现状、水资源质量状况和开发利用等情况,并对水资源供需发展趋势作出预测。根据西北地区水环境安全面临的严峻形势,提出了构建西北地区水环境安全体系的对策和建议。  相似文献   
986.
In this study, we tested the effects of dietary nickel on the activity of glutathione S-transferase (GST), esterases, phenoloxidase, and encapsulation in the haemolymph of larvae of the greater wax moth Galleria mellonella. We also explored the effects of dietary nickel on larval resistance to infection by the fungus Beauveria bassiana. Larvae fed a low dose of nickel (10 μg g−1) had significantly higher GST, phenoloxidase activity and encapsulation responses than controls fed on a nickel-free diet. We also found that larvae fed a sublethal dose of nickel (50 μg g−1) had increased GST, esterase activity and encapsulation rates but decreased phenoloxidase activity. Although, a sublethal dose of dietary nickel enhanced innate immunity, we found that this reduced resistance against the real pathogen. Our results suggest that enhanced immunity and detoxification enzyme activity of insects may not be beneficial to resistance to fungal infection. It appears that there is a trade off between different resistance mechanisms in insects under different metal treatments.  相似文献   
987.
依据国家相关标准对某退役后辐照装置周围的辐射水平进行监测与评价,通过数据评价得出该单位辐照装置退役场所未受到放射性污染,其退役后对环境的辐射影响可以忽略。  相似文献   
988.
放射源管理系统是一种基于环境地理信息系统平台的资源管理系统,是GIS技术与环境监测技术、环境管理技术、数据库技术等各种环境信息分析和处理技术的集成。系统为环保部门提供了一个功能强大的空间信息服务和管理工具,可以直观、方便地获取放射源的监控、管理等数据信息,为环境管理部门的决策提供依据。  相似文献   
989.
以深圳市宝安区为例,探讨以再生水满足城市水系环境需水的方法.应用一维恒定与非恒定水质模型计算了4种补水水质方案下该区10条主要河流的环境需水量,从水量平衡角度提出全区再生水BOD5的平均值,并进一步分析了补水水质与河流环境需水量的关系.结合该区水系与污水处理系统空间位置,提出3种再生水的空间配置方法.结果表明:茅洲河和...  相似文献   
990.
在反复实验的基础上建立了运用Bran+Luebbe AutoAnalyzer 3流动注射分析仪快速测定地表水中总氰化物的分析方法。结果表明,该方法与传统的分光光度法相比,具有自动进样、分析速度快、测定成本低等优点。与经典的分析方法相对照,结果无显著性差异,能够满足大批量地表水监测的要求。在测试系统中引入了恒温槽,进一步提高了测试的精密度和准确度。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号