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   186篇
  免费   1篇
  国内免费   4篇
安全科学   3篇
废物处理   8篇
环保管理   23篇
综合类   34篇
基础理论   28篇
污染及防治   54篇
评价与监测   33篇
社会与环境   8篇
  2023年   10篇
  2022年   7篇
  2021年   18篇
  2020年   3篇
  2019年   5篇
  2018年   5篇
  2017年   7篇
  2016年   4篇
  2015年   5篇
  2014年   6篇
  2013年   24篇
  2012年   9篇
  2011年   9篇
  2010年   9篇
  2009年   8篇
  2008年   9篇
  2007年   6篇
  2006年   2篇
  2005年   7篇
  2004年   4篇
  2003年   5篇
  2002年   2篇
  2001年   1篇
  1999年   1篇
  1998年   2篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1993年   2篇
  1992年   1篇
  1991年   2篇
  1990年   4篇
  1989年   1篇
  1982年   1篇
  1971年   2篇
  1966年   2篇
  1964年   1篇
  1963年   1篇
  1959年   1篇
  1957年   1篇
排序方式: 共有191条查询结果,搜索用时 46 毫秒
91.
The objective of this experiment is to study the potential ability of Salvinia natans L. to use in phytoassay for the cadmium toxicity in ecotoxicological studies. It is a simple and cost competitive method. The sensitivity of S. natans in terms of biochemical changes and enzyme activities to Cd2+ was remarkably noticeable. The catalase and protease activity was significantly decreased in the presence of cadmium, with increase of peroxidase and superoxide dismutase activity. The level of protein, carbohydrate and chlorophyll decreased and proline content increased in plants. The maximum permissible concentration of cadmium in different general water quality standards was evaluated and found that cadmium standard is not stringent enough.  相似文献   
92.
This communication presents the results of an investigation conducted on color removal from a monoazo acid dye, C.I. Acid Red 88, by adsorption onto coal based sorbents like Lignite coal, Charfines and Bituminous coal and F-400 Activated carbon and by chemical coagulation employing Aluminum sulfate, Ferric chloride, Manganese sulfate, Manganese chloride and Barium chloride.  相似文献   
93.
Starting with the intensification of irrigation activities in the beginning of 1980s in Abaya and Chamo lakes area, the decreasing water inflow to the lakes caused denudation of the wetlands. The ecological situation in the lake region changed significantly during last four decades. The lakes and associated wetlands change have been studied using Landsat MSS (1973), Landsat TM (1986), and Ladsat ETM (2000) satellite imagery. Along with satellite imagery, other hydro-meteorological data were collected and hydro-meteorological data analyses were done to assess the variability of wetlands. From these data, lakes morphometric property estimation at different time series and water balance analysis for both lakes were done. Wetlands are mapped from the TCT image and these maps are subject to change detection to see the temporal and spatial variability of the wetlands. Moreover, the lake-morphometric area and volume variation have been studied. The result showed that between 1986 and 2000, a significant reduction has been observed but lesser than the previous decades (6.4 km(2)). The identified reason behind this change is that the free settlement and shoreline cultivation of the wetlands causing the soil erosion and eventually adds the sediment to the wetlands.  相似文献   
94.
Environmental Science and Pollution Research - Polyvinylidene fluoride (PVDF) blended with varying concentrations of titanium nanotubes (TNT) was electrospun to result in a nanocomposite filter...  相似文献   
95.
Environmental Science and Pollution Research - The present work aims to investigate seasonal variations in air pollution levels in Lucknow and assess the ambient air quality of the city together...  相似文献   
96.
Environmental Science and Pollution Research - This paper intends to show the aspects of an environment-friendly hybrid energy system (HES) for reducing the electrical power problems in remote...  相似文献   
97.
98.
This research has developed mathematical models for computing lifetime greenhouse gas (GHG) emissions associated with materials. The models include embodied carbon (EC) emissions from the manufacture of materials, and GHG emissions from incineration, or landfill gas (LFG) production from landfill disposal of the material beyond their service lives. The models are applicable to all materials; however, their applications here are demonstrated for the lumber from a residential building with 50- and 100-year service lives, and with incineration, landfill, and deconstruction as end-of-life treatments. This paper introduces a new metric for lifetime GHG emissions associated with materials termed “Global Warming Impact of Materials (GWIM).” The GWIM is subdivided into two portions: (i) productive portion (GWIMp) that includes the materials’ emissions until the service life of the facility and (ii) non-productive portion (GWIMnp) which includes the materials’ GHG emissions beyond the service life until they are eliminated from the atmosphere. In place of the current, static, EC measurements (kgCO2e or MTCO2e), this model reports the GWIMs in units of kgCO2e-years or MTCO2e-years, which includes the effects of “time of use” of a facility. Using the models, this paper has computed GHG reductions by deconstruction, with material recoveries of 30%, 50%, and 70% at demolition for reuse, recycle, or repurpose. A 70% material recovery, after a 50-year service life of the building, affected a savings of 47% and 52% if the remaining 30% debris was incinerated or landfilled respectively. All of the values computed using models checked out with manual calculations.  相似文献   
99.
A three-dimensional regression analysis attempted to model mesozooplankton (MSP) biomass using sea surface temperature (SST) and chlorophyll-a (Chl-a). The study was carried out from January 2014 to July 2015 in the southwestern Bay of Bengal (BoB) and sampling was carried out on board Sagar Manjusha and Sagar Purvi. SST ranged from 26.2 to 33.1 °C while Chl-a varied from 0.04 to 6.09 μg L?1. During the course of the study period, there was a weak correlation (r?= 0.32) between SST and Chl-a statistically. MSP biomass varied from 0.42 to 9.63 mg C m?3 and inversely related with SST. Two kinds of approaches were adopted to develop the model by grouping seasonal datasets (four seasonal algorithms) and comprising all datasets (one annual algorithm). Among the four functions used (linear, paraboloid, the Lorentzian and the Gaussian functions), paraboloid model was best suited. The best seasonal and annual algorithms were applied in the synchronous MODIS-derived SST and Chl-a data to estimate the MSP biomass in the southwestern BoB. The modelled MSP biomass was validated with field MSP biomass and the result was statistically significant, showing maximum regression coefficient for the seasonal algorithms (R2?=?0.60; p?=?0.627; α?= 0.05), than the annual algorithm (R2?=?0.52; p?=?0.015, α?=?0.05).  相似文献   
100.
In January 2011, the idea of Millennium Consumption Goals (MCGs) was first proposed at the United Nations, because unsustainable patterns of consumption and production have led to multiple problems threatening the future of humanity. The global economy driven by consumption already uses natural resources equivalent to almost 1.5 planets earth, with the world's richest 1.4 billion consuming almost 85% of global output, which is over 60 fold the consumption of the poorest 1.4 billion. The consumption of the rich is not only ecologically unsustainable, but also “crowding out” the prospects of the poor and exacerbating inequalities that increase the risk of conflict and global unrest. The MCGs provide an innovative future vision and complement the Millennium Development Goals (MDGs) that aim to help the world's poor. First, the MCGs seek to address the issues of global poverty and inequality by ensuring that the basic consumption needs of over 2 billion poor people are met. Next, the MCGs will provide benchmarks for the consumption of the rich, which will reduce the burden on the world's natural resource base. Instead of viewing the affluent as a problem, the novel approach of the MCGs would persuade them to contribute to the solution without having to reduce their quality of life. The MCGs apply even‐handedly to the rich in all countries. The concept enjoys broad support worldwide and is being promoted by a global coalition called the MCG Initiative (MCGI). A bottom‐up approach has already been started by many pioneering individuals, communities, organizations, firms, cities, regions and nations. They prefer not to wait for broad multilateral agreements and are acting now, to voluntarily pursue their own specific MCGs. A parallel top‐down path is being pursued through mandatory agreements at the United Nations/international level, starting with the Rio+20 Earth Summit and beyond. The MCGs fit in with other major UN initiatives like Agenda 21, the MDGs, green economy, SCP and the Sustainable Development Goals.  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