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   2241篇
  免费   253篇
  国内免费   941篇
安全科学   185篇
废物处理   120篇
环保管理   267篇
综合类   1765篇
基础理论   439篇
污染及防治   391篇
评价与监测   74篇
社会与环境   148篇
灾害及防治   46篇
  2024年   6篇
  2023年   30篇
  2022年   90篇
  2021年   91篇
  2020年   76篇
  2019年   79篇
  2018年   60篇
  2017年   98篇
  2016年   98篇
  2015年   116篇
  2014年   143篇
  2013年   189篇
  2012年   186篇
  2011年   191篇
  2010年   173篇
  2009年   166篇
  2008年   119篇
  2007年   214篇
  2006年   226篇
  2005年   184篇
  2004年   146篇
  2003年   126篇
  2002年   106篇
  2001年   87篇
  2000年   90篇
  1999年   72篇
  1998年   57篇
  1997年   39篇
  1996年   29篇
  1995年   36篇
  1994年   32篇
  1993年   19篇
  1992年   16篇
  1991年   14篇
  1990年   4篇
  1989年   2篇
  1988年   8篇
  1987年   2篇
  1983年   1篇
  1982年   4篇
  1980年   2篇
  1979年   1篇
  1978年   2篇
  1973年   2篇
  1971年   1篇
  1970年   1篇
  1967年   1篇
排序方式: 共有3435条查询结果,搜索用时 15 毫秒
991.
介绍了美国REDFOX公司生产的新型污水处理系统的结构和原理,系统很好地解决了野外施工现场生活污水处理过程中存在的问题。  相似文献   
992.
993.
鱼类实验动物的生物学特性及应用   总被引:3,自引:0,他引:3  
本文阐述了鱼类实验动物的生物学特性,并综述了其作为实验动物在生物医学研究中的应用现状.  相似文献   
994.
ABSTRACT: Bluegills were exposed for one hour to 0.2 or 2.3 mg/liter water soluble fraction (WSF) of JP-4 in a testing chamber designed to contain individual fish. A strain gage paddle was used to monitor activity. Whole body movement of individual fish did not change appreciably during exposure to either 0.2 or 2.3 mg/liter WSF-JP-4. Strength of pectoral fin movement, accounting for the majority of the fish behavior, increased in six of ten individuals exposed to 2.3 mg/liter WSF-JP-4. Pectoral fanning may be a useful parameter to indirectly assess water quality.  相似文献   
995.
近50年来江汉湖群水域演化定量研究   总被引:13,自引:2,他引:11  
根据江汉平原湖区发育背景、资源环境结构和社会经济功能等方面因素,将研究区界定为湖北省境内以江汉平原为依托、海拔50 m等高线以内的所有地区。其范围在东经 111°36′38.76″~116°7′52.14″、北纬29°25′59.25″~31°27′14.45″之间,按自然界线计算面积4.664万km2,按行政区统计面积为6.475万km2。运用RS/GIS技术,分析得知:近50年来,江汉湖群湖泊总数量和总面积均表现出总体下降、中间年份有波动的趋势,20世纪50年代、60年代、70年代、80年代、90年代和21世纪初(2000年),0.1 km2以上的湖泊总数量分别是1 309、611、612、838、768、771个,0.1 km2以上的湖泊总面积分别是8 503.7、5 462.5、2 933.8、2 977.3、3 451.4、3 188.1 km2。围湖垦殖是近50多年来江汉湖群演化的主要原因和主导因子。  相似文献   
996.
Unique mountain-steppe ecosystems in the Southern Urals have retained a high level of species and cenotic diversity, despite fragmentation and isolation. Specific features of these ecosystems are described.  相似文献   
997.
Microscale Spatial Variation in Forest Litter Phytotoxicity   总被引:1,自引:0,他引:1  
The spatial variation (within a 100 × 100 m plot) in the pollution of forest litter with heavy metals (Cu, Cd, Pb, and Zn), its acidity, and phytotoxicity (measured by the results of the root test using seedlings from a genetically homogeneous sample of common dandelion (Taraxacum officinale s.l.) have been estimated. Forest litter has been sampled in three zones differing in the toxic impact of long-term polymetal pollution by emissions from a copper-smelting plant emissions in the Middle Urals. The phytotoxicity variation is maximum in a moderately polluted plot, where both very high and very low pollution levels were observed, which determines a substantially nonlinear dose–effect relationship. The litter phytotoxicity is mainly accounted for by exchangeable forms of metals. Biological testing of samples from the most polluted plot has demonstrated marked antagonism between heavy metals and acidity.  相似文献   
998.
浅析Biostyr工艺   总被引:1,自引:0,他引:1  
王忠 《交通环保》2002,23(1):35-37
介绍Biostyr(一种新型曝气生物滤池 ) ,着重该工艺的结构、工作原理及工艺特点。  相似文献   
999.
An intense waste management (WM) planning activity is currently undergoing in England to build the infrastructure necessary to treat residual wastes, increase recycling levels and the recovery of energy from waste. From the analyses of local WM strategic and planning documents we have identified the emerging of three different energy recovery strategies: established combustion of residual waste; pre-treatment of residual waste and energy recovery from Solid Recovered Fuel in a dedicated plant, usually assumed to be a gasifier; pre-treatment of residual waste and reliance on the market to accept the ‘fuel from waste’ so produced. Each energy recovery strategy will result in a different solution in terms of the technology selected; moreover, on the basis of the favoured solution, the total number, scale and location of thermal treatment plants built in England will dramatically change. To support the evaluation and comparison of these three WM strategy in terms of global environmental impacts, energy recovery possibilities and performance with respect to changing ‘fuel from waste’ market conditions, the LCA comparison of eight alternative WM scenarios for a real case study dealing with a large flow of municipal wastes was performed with the modelling tool WRATE. The large flow of waste modelled allowed to formulate and assess realistic alternative WM scenarios and to design infrastructural systems which are likely to correspond to those submitted for approval to the local authorities. The results show that all alternative scenarios contribute to saving abiotic resources and reducing global warming potential. Particularly relevant to the current English debate, the performance of a scenario was shown to depend not from the thermal treatment technology but from a combination of parameters, among which most relevant are the efficiency of energy recovery processes (both electricity and heat) and the calorific value of residual waste and pre-treated material. The contribution and relative importance of recycling and treatment/recovery processes change with the impact category. The lack of reprocessing plants in the area of the case study has shown the relevance of transport distances for recyclate material in reducing the efficiency of a WM system. Highly relevant to the current English WM infrastructural debate, these results for the first time highlight the risk of a significant reduction in the energy that could be recovered by local WM strategies relying only on the market to dispose of the ‘fuel from waste’ in a non dedicated plant in the case that the SRF had to be sent to landfill for lack of treatment capacity.  相似文献   
1000.
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