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   128篇
  免费   0篇
  国内免费   2篇
安全科学   4篇
废物处理   10篇
环保管理   12篇
综合类   18篇
基础理论   22篇
污染及防治   26篇
评价与监测   26篇
社会与环境   12篇
  2023年   4篇
  2022年   11篇
  2021年   3篇
  2020年   2篇
  2019年   1篇
  2018年   6篇
  2017年   6篇
  2016年   7篇
  2015年   1篇
  2014年   6篇
  2013年   19篇
  2012年   5篇
  2011年   12篇
  2010年   6篇
  2009年   5篇
  2008年   4篇
  2007年   3篇
  2006年   7篇
  2005年   2篇
  2004年   2篇
  2003年   1篇
  2002年   2篇
  2000年   3篇
  1996年   1篇
  1989年   1篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1980年   1篇
  1961年   1篇
  1959年   1篇
  1958年   1篇
  1957年   1篇
排序方式: 共有130条查询结果,搜索用时 31 毫秒
81.
India has a large number of paper manufacturing units, with mills varying in size of operations and type of product, scattered all over the length and breadth of the country. Present study deals with the survey of four different pulp and paper mills (Mill A, Mill B, Mill C and Mill D) in India, differing in their scale of operation as well as raw material usage. Physico-chemical characterization of wastewaters produced by different processing units like digestor house liquors, bleaching section, paper machine backwaters, combined inlet to the ETP and outlet to ETP, for all the four mills, was conducted. Different parameters like pH, Color, COD, BOD, percent Na, SAR, TDS and Total hardness were analyzed and compared. Highly significant differences were thus found between all the processing units of all four mills with p values < 0.01. This evaluation showed that though these mills have effluent treatment facilities installed in their premises, improvements are still needed to increase their efficiencies for treating the discharged wastewaters.  相似文献   
82.
Horseshoe crabs act as moving substrata for simple to complex communities of small marine organisms. Amplexed adult pairs migrate for breeding once every 2 weeks from deep waters towards nearshore waters during highest high tide. Female horseshoe crabs bury themselves to the level of the lateral eyes to deposit eggs while the male crabs fertilize them. Subsequently eggs are buried by the female. Tachypleus gigas (Müller) is the most abundant horseshoe crab species above available along the Orissa coast (India). Adults reach terminal anecdysis once sexually mature and live with their carapace for 4 to 9 years. In spite of this, epibiosis is limited. In the current investigation, differences in the epibiotic community (diatoms and macro-epibionts) present on horseshoe crabs, according to gender, were evaluated, and the macro-epibiont population from different regions of the carapace was mapped. In general, female horseshoe crabs harbored fewer epibionts than the males. Among the diatoms, Navicula spp., Nitzschia spp. and Skeletonema sp. were dominant in both sexes. However, the abundance and diversity of diatoms was greater on the carapaces of male crabs. Among the macro-epibionts, the acorn barnacle (Balanus amphitrite Darwin) and encrusting bryozoan (Membranipora sp.) were the most dominant forms. Barnacles and bryozoans were greater in abundance in the “rough” zone (cardiopthalmic region and anterior region of the opisthosoma). Mapping of the macro-epibionts from different regions of the carapace revealed differential distribution in males and females. Such differentiated distribution of the macro-epibionts can be related to factors such as changing habitat by the horseshoe crabs during breeding, mechanical abrasion and surface availability during mating and nesting periods, requirements of epizootic larvae and surface properties of the carapace (wettability and roughness). In the case of females, mechanical abrasion and surface availability played an important role in the epibiotic community structure and distribution patterns. The surface wettability measurements indicated male carapace to be slightly more hydrophobic than the female carapace. Scanning electron microscopy revealed that the male carapace was comparatively rough compared to the smooth carapace of females. A comparison of surface properties of the carapace indicated that the male carapace is more conducive for epibiosis. Received: 23 August 1999 / Accepted: 25 January 2000  相似文献   
83.
Environmental Science and Pollution Research - The correct presentation of Eq. 10 is shown in this paper.  相似文献   
84.
85.
Agriculture consumes more than two-thirds of global fresh water out of which 90 % is used by developing countries. Freshwater consumption worldwide is expected to rise another 25 %by 2030 due to increase in population from 6.6 billion currently to about 8 billion by 2030 and over 9 billion by 2050. Worldwide climate change and variability are affecting water resources and agricultural production and in India Ganga Plain region is one of them. Hydroclimatic changes are very prominent in all the regions of Ganga Plain. Climate change and variability impacts are further drying the semi-arid areas and may cause serious problem of water and food scarcity for about 250 million people of the area. About 80 million ha out of total 141 million ha net cultivated area of India is rainfed, which contributes approximately 44 % of total food production has been severely affected by climate change. Further changing climatic conditions are causing prominent hydrological variations like change in drainage density, river morphology (tectonic control) & geometry, water quality and precipitation. Majority of the river channels seen today in the Ganga Plain has migrated from their historic positions. Large scale changes in land use and land cover pattern, cropping pattern, drainage pattern and over exploitation of water resources are modifying the hydrological cycle in Ganga basin. The frequency of floods and drought and its intensity has increased manifold. Ganga Plain rivers has changed their course with time and the regional hydrological conditions shows full control over the rates and processes by which environments geomorphically evolve. Approximately 47 % of total irrigated area of the country is located in Ganga Plain, which is severely affected by changing climatic conditions. In long run climate change will affect the quantity and quality of the crops and the crop yield is going to be down. This will increase the already high food inflation in the country. The warmer atmospheric temperatures and drought conditions will increase soil salinization, desertification and drying-up of aquifer, while flooding conditions will escalate soil erosion, soil degradation and sedimentation. The aim of this study is to understand the impact of different hydrological changes due to climatic conditions and come up with easily and economically feasible solutions effective in addressing the problem of water and food scarcity in future.  相似文献   
86.
A field experiment was conducted at Anand Agricultural University, Anand during Sept-Dec, 2009 to study the rate of degradation of flubendiamide in/on brinjal fruits following foliar application of Fame 480 SC at 90 (standard dose) and 180 (double dose) g a.i. ha(?-1). The residues estimated using HPLC revealed persistence of flubendiamide in/on brinjal till 3rd and 7th day after the last spray at standard and double dose, respectively. The residues of flubendiamamde were reported as parent compound, and no desiodo metabolite was detected. The initial deposits of 0.17 and 0.42 μg g(?-1) in/on brinjal fruits reached below determination level of 0.05 μg g(?-1) on the 5th and 10th day at standard and double dose, respectively. The half life of flubendiamide on brinjal fruits ranged from 2.68 to 2.55 days. Soil samples analyzed on the 15th day after the last spray revealed residues at below determination level (0.05 μg g(?-1)) at either dose of application.  相似文献   
87.
Environmental Science and Pollution Research - Vanadium pentoxide can be an inexpensive replacement to vanadium sulfate in synthesizing vanadium redox flow battery (VRFB) electrolytes. In this...  相似文献   
88.
The biggest challenge of the 21st century is to satisfy the escalating demand of energy and minimize the globally changing climate impact. Earth to air heat exchanger (EAHE) system can effectively reduce heating affects on buildings. An experimental study was carried out by designing EAHE system using low cost building materials like Bamboo (Bambuseae) and hydraform (cement and soil plaster) to reduce the energy consumption of buildings and minimize the impact of climate change. This system utilizes earth’s constant subterranean temperature for naturally heating or cooling the inlet air. This study was carried out in the North Eastern part of India. An open loop EAHE system was developed to predict the heating and cooling potential of the system. Within the system locally available bamboos were used for constructing the tunnel pipes and soil-cement mixture plaster was used to enhance the conductivity of the bamboo pipes. Soil-cement mixtures are capable of decreasing the humidity by 30 to 40 %. Majority of the North Eastern region of India, have humid climatic conditions through out the year. Experiment was performed continuously for 7 days and the result shows that irrespective to the inlet air temperature (ranges from 35 °C to 42 °C), outlet air temperature was recorded between 25 °C and 26 °C, which shows the effectiveness of the system. After a series of experimental analysis the study reveals that underground tunnel based fresh air delivery system is one of the easily feasible and economically feasible techniques which can drastically reduce the energy consumption of the buildings and help in addressing the continuously escalating demand of power and minimizing the impact of changing climatic conditions on buildings.  相似文献   
89.
90.
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