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   1980篇
  免费   249篇
  国内免费   396篇
安全科学   415篇
废物处理   44篇
环保管理   512篇
综合类   908篇
基础理论   246篇
环境理论   4篇
污染及防治   146篇
评价与监测   110篇
社会与环境   131篇
灾害及防治   109篇
  2024年   9篇
  2023年   51篇
  2022年   63篇
  2021年   97篇
  2020年   99篇
  2019年   84篇
  2018年   66篇
  2017年   106篇
  2016年   149篇
  2015年   144篇
  2014年   104篇
  2013年   221篇
  2012年   175篇
  2011年   143篇
  2010年   111篇
  2009年   115篇
  2008年   76篇
  2007年   120篇
  2006年   102篇
  2005年   83篇
  2004年   59篇
  2003年   74篇
  2002年   53篇
  2001年   44篇
  2000年   29篇
  1999年   36篇
  1998年   19篇
  1997年   15篇
  1996年   16篇
  1995年   14篇
  1994年   17篇
  1993年   10篇
  1992年   14篇
  1990年   8篇
  1988年   8篇
  1987年   5篇
  1986年   5篇
  1982年   4篇
  1981年   6篇
  1980年   3篇
  1979年   6篇
  1978年   6篇
  1977年   8篇
  1976年   4篇
  1975年   2篇
  1974年   4篇
  1973年   6篇
  1972年   8篇
  1971年   11篇
  1970年   4篇
排序方式: 共有2625条查询结果,搜索用时 218 毫秒
131.
This paper explores the notion of environmentally induced spatial stigma through an analysis of data from interviews across public attitudes to pollution within the Asopos river basin in central Greece. The area has a 40 year plus history of legal and illicit industrial waste disposal and public debate on the associated environmental degradation. The study focuses on the perceptions and beliefs of a sector of the community likely to be directly and negatively affected by stigma, that is small business owners in the tourism and hospitality sector. The qualitative analysis explores awareness and viewpoints on environmental degradation and water quality within the local context, implications for the local economy and the individual's own enterprise, views on industrial environmental management as well as corporate responsibility and future prospects for the environmental problems of Asopos. Findings reveal a noticeable variation in views on industrial pollution and ecosystem deterioration among the respondents, but overall a strong environmentally induced stigmatization of the area. They also uncover an information asymmetry and lack of credible commitment by government bodies and industry members in disclosing accurate information, a situation likely to increase speculation and uncertainty within the community. The paper concludes by addressing implications of the findings to policy-making and managerial considerations, along with future research perspectives which aim to increase considerations of sustainability aspects for local development.  相似文献   
132.
When confronted with the demands of global climate change, what causes some policy-makers to move the climate adaptation agenda forward in their communities, while others seemingly get little accomplished? To answer this question, we first discuss work on policy-drivers in a coupled human–natural systemic context. This summary review of past research helps us develop a set of competing and complementary explanations for why some communities aggressively pursue climate adaptation policies, while others do less. Following the discussion of policy-drivers, we then undertake an aggregate-level analysis of data collected across the 169 towns in Connecticut regarding climate adaptation, thus linking policy to its fundamental global cause. The quantitative data are augmented with interview data from policy-makers and activists from around the New England region.  相似文献   
133.
Most of the energy conversion in industrial devices and equipment is completed by the motor. The acquirement of motor parameters becomes very important for designing the motor drives. The aim of this paper is to design and implement a motor measurement system. Through the processing of an Advanced RISC Machines (ARM) microcontroller, the various parameters of motors such as input voltage, input current, input power, motor speed, and motor torque can be obtained. Consequently, the torque constant, load torque, viscous friction, and the inertia of the motor are calculated and achieved. The motor parameters can be commanded and displayed in the designed human interface of a PC via USB communication. The hardware system designed in this system includes an ARM microcontroller, an inverter, a voltage sensor, a current sensor, a torque sensor, and power supply. The software programming is developed under the Visual Studio 2012 environment development platform using the C language. Finally, the prototype of the motor measurement system is completed and verified. The experimental results for the motor parameters and torque/speed characteristic are demonstrated and show the feasibility of the complete designed system.  相似文献   
134.
Using meteorological and electricity demand data for a 4-year period, electricity demand in Shetland was modeled to provide an estimate of the demand over a 30-year period from 1 January 1981. That modeled demand was then compared to estimated wind power output over the same period using the WAsP model. The wind farm output was estimated for a range of sizes of wind farm up to the consented 370 MW Viking Wind Farm in Shetland. Some wind power was available for 94% of the time and the 370 MW wind farm would meet 100% of demand for nearly 80% of the time. The statistics of single and accumulated deficits were calculated for a range of wind farms and estimates of the amount of additional generation capacity and additional power requirements were assessed. The study suggests that with storage, wind power in Shetland could meet all electricity demand in Shetland at around £130 to £150/MWh (excluding subsidy) and with a grid connection allowing the sale of excess power, those costs could be reduced.  相似文献   
135.
Western China has lagged a lot in terms of industrial structure and economic development,compared with the national average.And China announced its target of CO_2 emission reduction,i.e.by 2020,CO_2 emission per GDP will drop by40-45%compared with 2005.The target will be incorporated into China's long-term industrial planning.Against this background,this paper will make a comprehensive examination of the industrial development of Western China,aiming to discover a green and compatible way.First,we analyze the spatiotemporal evolution of regional industrial structure for the period 2000-2010.Second,we try to discover the industrial structure optimization path for Western China by employing the Vector Auto Regression model.Lastly,we try to provide some advice and suggestions for further industrial development in Western China.Our examination shows that further industrial development in Western China should pay full attention to resource conservation and recycling,and develop on a green and compatible path.  相似文献   
136.
This work applies optimization and an Eulerian inversion approach presented by Bagtzoglou and Baun in 2005 in order to reconstruct contaminant plume time histories and to identify the likely source of atmospheric contamination using data from a real test site for the first time. Present-day distribution of an atmospheric contaminant plume as well as data points reflecting the plume history allow the reconstruction and provide the plume velocity, distribution, and probable source. The method was tested to a hypothetical case and with data from the Forest Atmosphere Transfer and Storage (FACTS) experiment in the Duke experimental forest site. In the scenarios presented herein, as well as in numerous cases tested for verification purposes, the model conserved mass, successfully located the peak of the plume, and managed to capture the motion of the plume well but underestimated the contaminant peak.  相似文献   
137.
为探索河流水质模型参数新的求解方法,根据有限的实测数据,分别应用免疫进化优化算法和免疫进化优选的捕食搜索算法,对河流水质模型计算公式中的多参数进行优化。将优化得到的计算公式用于国内外若干河流的河段中DO浓度值的拟合,并与实测结果进行了比较。结果表明,将免疫进化优化算法或免疫进化优选的捕食搜索算法优化得到的水质模型参数精度不仅较高,而且相对稳定,从而为河流水质模型参数的优化提供了一种新方法。  相似文献   
138.
电除尘设备在减少工业粉尘排放量、降低大气环境污染、保护生态环境等方面有着重要的作用,随着我国对节能减排工作的重视及环保要求的提高,保证其安全、稳定、经济、节能运行成为火电厂环保工作重点。对北仓电厂三期2×1000 MW机组电除尘电场供电方式优化、电除尘振打方式优化、电除尘闭环控制技术、电除尘高频电源技术、电除尘灰斗、瓷套蒸汽加热技术组合集成应用进行了研究,在确保除尘效率达到要求的情况下,降低运行电耗。相关的电除尘深度节能技术成果在国内同类型设备中具有一定的借鉴意义。  相似文献   
139.
采用化学除油降黏—污泥调理—离心脱水工艺处理某炼油厂废水处理系统的混合污泥,并对工艺条件进行优化。实验结果表明,最佳的工艺条件为:化学除油降黏阶段处理体系的pH=4,反应温度35 ℃,H2O2加入量 2 g/L,m(H2O2)∶ m(Fe2+)=4,反应时间 60 min;污泥调理反应阶段的CaO加入量7.0 g/L;离心脱水阶段在分离因数为1 558时脱水5 min。在此条件下,得到的泥饼的含水率为70.0%~75.0%(w),含油率小于2%(w),污泥比阻约为3.0×107 s2/g。  相似文献   
140.
鼠李糖脂洗脱氯丹和灭蚁灵污染场地土壤的工艺参数   总被引:3,自引:0,他引:3  
优化了鼠李糖脂洗脱氯丹、灭蚁灵污染土壤的工艺条件,为开展有机氯农药污染场地土壤洗脱修复工程实践提供科学依据和技术参数。实验结果表明,随着洗脱剂———鼠李糖脂浓度的增加,氯丹和灭蚁灵的洗脱量呈现先增加后降低的趋势;洗脱时间和液固比对洗脱效果的影响趋势与浓度相同;在0~120 r/min范围内,氯丹和灭蚁灵洗脱量随着搅拌速度的增加而增大,80、120和200 r/min的洗脱量间差异不显著;单次洗脱量随洗脱次数的增加而降低,累计洗脱量则逐渐增大。综上所述,氯丹、灭蚁灵污染场地土壤鼠李糖脂洗脱的适宜工艺参数为鼠李糖浓度10 mmol/L,搅拌速度80 r/min,固液比1∶10,洗脱时间20 min,洗脱3次。  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