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   219篇
  免费   1篇
  国内免费   3篇
安全科学   1篇
废物处理   15篇
环保管理   18篇
综合类   14篇
基础理论   58篇
污染及防治   60篇
评价与监测   36篇
社会与环境   20篇
灾害及防治   1篇
  2023年   7篇
  2022年   18篇
  2021年   12篇
  2020年   1篇
  2019年   3篇
  2018年   12篇
  2017年   7篇
  2016年   4篇
  2015年   6篇
  2014年   3篇
  2013年   24篇
  2012年   14篇
  2011年   14篇
  2010年   7篇
  2009年   5篇
  2008年   10篇
  2007年   9篇
  2006年   11篇
  2005年   11篇
  2004年   11篇
  2003年   8篇
  2002年   5篇
  2000年   2篇
  1999年   2篇
  1998年   2篇
  1996年   1篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1982年   1篇
  1964年   1篇
  1963年   1篇
  1962年   1篇
排序方式: 共有223条查询结果,搜索用时 15 毫秒
51.
The oxidation of elemental sulphur in the catalytic presence of selected metal ions [Cr(III), Ce(III), Cu(II), Hg(II), Ni(II), Co(II), Mo(VI), Cd(II), Zn(II), Ti(IV), and V(V)], and hydrocarbons (benzene, gasoline, and kerosene) was studied in an alkaline medium buffered by marble powder. The catalytic efficiencies of metal ions were: Cr(III) > Ce(III) > Cu(II) > Hg(II) > Ni(II). The oxidation process was inhibited in the presence of other ions, and the inhibitive effect was in the following order: Co(II) < Mo(VI) < Cd(II) < Zn(II) < Ti(IV) < V(V). In the case of hydrocarbons, the efficiencies were as follows: gasoline > benzene > kerosene. The oxidation of sulphur in sulphur-loaded soils obtained from near a textile mill and a distillery were also carried out in the c both cases was significantly enhanced.To whom all correspondence should be addressed.  相似文献   
52.
Environmental Science and Pollution Research - Solar power is one of the main sources of renewable energy which helps for protecting the environmental and reducing pollution. Technologies and...  相似文献   
53.
Plasma Ca concentration (annual mean) in males Coturnix cotumix coturnix was 10.27 +/- 0.14 mg/100 ml while it was slightly higher (11.85 +/- 0.15 mg/100 ml) among females. Plasma Pi levels (annual mean) in males and females were 5.62 +/- 0.12 mg/100 ml and 6.52 +/- 0.20 mg/100 ml, respectively. While the males did not exhibit marked fluctuation in plasma Ca and Pi levels either in winter or summer, the females did record significant elevation in the levels of both these electrolytes during breeding season. The peak values of plasma Ca (17.66 +/- 0.38 mg/100 ml) and Pi (8.64 +/- 0.22 mg/100 ml) in females were observed during June. Parathyroid gland of the grey quail exhibited hyperactivity (hypertrophy and hyperplasia) during breeding season, however, the activity was more conspicuous among females than in males. The maximum increase in cell and nuclear diameters were observed in females during May-July. The follicles were also filled with AF- and PAS-positive materials during these months. The glands depicted signs of hypoactivity and degeneration during peak winter season (November-December) as evident by decrease in cell and nuclear diameters as well as vacuolation in the chief cells.  相似文献   
54.
Pandey S  Singh DK 《Chemosphere》2006,63(5):869-880
Chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2 pyridyl phosphorothioate) 20 EC and Quinalphos (O,O-diethyl O-quinoxalin-2-yl phosphorothioate) 25 EC, were applied in groundnut (Arachis hypogaea L.) field as seed treatment at 25 ml/kg and soil treatment at 4 l/ha in 1998 and 1999. The residues of these insecticides were monitored during the entire crop season and their effect on the soil enzymes dehydrogenase, phosphomonoesterase and arginine deaminase were studied. Ninety nine percent of chlorpyrifos residues were dissipated within 60 days from seed treated soil and 98% dissipation was observed in soil treated field for the same days. Its half lives in seed treated soil were 8 days and 7 days and in soil treated field were 9.2 days in and 7.5 days in 1998 and 1999 respectively. Dissipation of quinalphos in comparison to chlorpyrifos was slow both in seed treated and soil treated field. Eighty seven percentage to 92% dissipation of quinalphos residues were observed from seed treated soil and 98% residues were dissipated from soil treated field within 75 days. Its half lives in seed treated soil were 20 days and 18 days and in soil treated field, its half lives were 13 days and 17 days 1998 and 1999 respectively. Inhibition in dehydrogenase activity followed by recovery was observed both in seed and soil treatments with chlorpyrifos. An inhibition of 17.2% was estimated after 60 days of seed treatment in comparison to control. Dehydrogenase activity was significantly reduced to 63% after 15 days of quinalphos seed treatment in comparison to control in 1998. Similar trends were observed in 1999. A significant inhibition in dehydrogenase activity was observed after soil treatment both in 1998 and 1999. Phosphomonoesterase activities were significantly inhibited upto 25.2% as compared to the control, on the 15th day of chlorpyrifos seed treatment in 1998 and similarly, after one day of treatment in 1999. Quinalphos inhibited the phosphomonoesterase activity till the end of the experimental period in the soil treated fields, whereas recovered within 30-60 days of treatment in the seed treated fields. Arginine deaminase activity was significantly stimulated within one day after chlorpyrifos seed and soil treatments in both years. The activity was almost threefold higher on the 30th and the 15th day of soil treatment in 1998 and 1999, respectively. A temporary inhibition of arginine deaminase activity was observed after quinalphos treatment. It was observed that in most of cases insecticides have temporary inhibitory effect on soil enzymes. However, inhibition was smaller in seed treated soil than in direct soil treatment.  相似文献   
55.
Compost was prepared from wheat straw enriched with Rajasthan rock phosphate and Aspergillus awamori. The resulting phospho-compost along with phosphorus enriched FYM, mineral fertilizer (rock phosphate) and super phosphate were evaluated for their individual contribution in improving organic matter status, P availability, and enzymatic activities of soil under wheat crop grown in a micro plot. The results showed that total organic carbon, nitrogen, microbial biomass, and humus content (an index of organic matter status of soil) of soil was highest when farm yard manure (FYM) after its enrichment with 12.5% rock phosphate was applied. Microbial enriched phospho-compost was the product yielding highest soil available phosphorus, phosphorus uptake, urease, and cellulase activities. However, FYM amended with 25% rock phosphate resulted in the greatest enhancement of beta- glucosidase. Measured parameters indicated a sure improvement of chemical and biological activities of soil after the application of phosphorus enriched organic amendments compared to the commercial fertilizer commonly used by the Indian farmers.  相似文献   
56.
Assessment of physicochemical parameters of Ganga Canal water was carried out during 2012–2013 at Haridwar (Uttarakhand) with two different sites, i.e., Bhimgoda Barrage (site 1—control site) and Bahadrabad (site 2—contaminated site), where canal water flows with loads of pollution from highly commercial and industrial areas. During investigation, maximum turbidity (287.72 ± 56.28 JTU), total solids (1167.60 ± 303.90 mg l?1), free CO2 (1.88 ± 0.22 mg l?1), total hardness (60.14 ± 1.13 mg l?1), pH (7.1 ± 0.13), nitrate (0.048 ± 0.010), nitrite (0.019 ± 0.001), biochemical oxygen demand (2.866 ± 1.098), chemical oxygen demand (6.8 ± 2.61) and phosphate (0.087 ± 0.015), while minimum velocity (1.71 ± 0.19 ms?1), transparency (0.12 ± 0.08 m) and dissolved oxygen (7.95 ± 0.44 mg l?1) were recorded in monsoon season at site 2 in comparison with site 1. The mean values of these parameters were compared with WHO and ISI standards and found significant differences (p < 0.05) in the mean values of turbidity, total solids, pH, dissolved oxygen, free CO2 and total hardness with sampling sites. The turbidity of both the sites 1 and 2 was recorded above the permissible limit. Turbidity of site 2 is much higher than of site 1, so it is counted as more polluted. The values of the studied parameters were more during monsoon season and summer season at site 2 as compared to site 1. The results indicated that most of the physicochemical parameters from Ganga Canal system were within or at periphery in comparison with permissible limit of ISI and WHO for drinking water and therefore may be suitable for domestic purposes, but it requires perceptible consideration due to intense changes in climate and increase in pollution.  相似文献   
57.
Isoproturon (IPU)-degrading soil bacteria were isolated from herbicide-applied wheat fields. These isolates were identified using cultural, morphological, biochemical and 16S rRNA sequencing methods. 16S rRNA sequences of both the bacterial isolates were compared with NCBI GenBank data base and identified as Bacillus pumilus and Pseudoxanthomonas sp. A soil microcosm study was carried out for 40 days in six different treatments. Experimental results revealed maximum 95.98% IPU degradation in treatment 6 where bacterial consortia were augmented in natural soil, followed by 91.53% in treatment 5 enriched with organic manure as an additional carbon source. However, only 14.03% IPU was degraded in treatment 1 (control) after 40 days. In treatments (2–4), 75.59%, 70.92% and 77.32% IPU degradation was recorded, respectively. IPU degradation in all the treatments varied significantly over the control. 4-Isopropylaniline was detected as IPU degradation by-product in the medium. The study confirmed that B. pumilus and Pseudoxanthomonas sp. performed effectively in soil microcosms and could be employed profitably for field-scale bioremediation experiments.  相似文献   
58.
Utilization of natural resources has multiplied globally, resulting in serious environmental deterioration and impeding the achievement of the Sustainable Development Goals (SDGs). For the harmonious development of human nourishment and the balance of nature, it is vital to evaluate environmental segments' resource usage, transformation, and residue, referred to as ‘footprint,’ in order to highlight carrying capacity and sustainability. This analysis highlights the Environmental Footprint (EF) of India per state from 2010 to 2020 in terms of hectares per capita. This study evaluates India's biological, hydrological, energy, ecological, and pollution footprints, carrying capacity, environmental pressure, and environmental deficit using 17 distinct parameters categorized under the themes of biological resource, hydrological resource, energy resource, and pollution concentration. We proposed a reoriented methodology and EF concepts that determine India's footprint, carrying capacity, nature of sustainability, environmental pressure index, and its consequential links to the 2030 SDGs. As a result, the biological resources contributed to ~50% of the environmental footprint, while hydrological, energy, and pollutants made up the remaining. Between 2010 and 2020, Delhi, Uttar Pradesh, Bihar, and West Bengal had the highest EF, while Jammu and Kashmir and the north-eastern provinces had the lowest. During the research period, the ecological deficit in India has increased overall. India impedes the 2030 SDGs; therefore, the study provides a picture of resource consumption, waste generation, economic growth, and societal changes, enabling academics and policymakers to redefine or document policy for a more sustainable future.  相似文献   
59.
There is growing recognition that teams do not function in a vacuum and that external boundary activities are important predictors of team performance, effectiveness, and knowledge sharing. In the past, researchers have focused on the effects of team composition or task characteristics as antecedents of critical boundary spanning activities. However, less effort has been directed at understanding how antecedents at multiple levels can simultaneously influence boundary spanning behavior in teams. This paper takes stock of over 20 years of research on the topic of team boundary spanning. Adopting a “bracketing” approach etc., we develop a multi‐level theoretical model to guide future research on the determinants of team boundary spanning. This model specifies task‐based, team‐level, and contextual antecedents of team boundary spanning and outlines the contingencies shaping the emergence of effective boundary‐management behavior in teams. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
60.
Increasing consciousness about future sustainable agriculture and hazard free food production has lead organic farming to be a globally emerging alternative farm practice. We investigated the accumulation of air-borne heavy metals in edible parts of vegetables and in cultivated soil horizon in organic farming system in a low rain fall tropical region of India. The factorial design of whole experiment consisted of six vegetable crops (tomato, egg plant, spinach, amaranthus, carrot and radish) x two treatments (organic farming in open field and organic farming in glasshouse (OFG)) x seven independent harvest of each crop. The results indicated that except for Pb, atmospheric deposition of heavy metals increased consistently on time scale. Concentrations of heavy metals in cultivated soil horizon and in edible parts of open field grown vegetables increased over time and were significantly higher than those recorded in OFG plots. Increased contents of heavy metals in open field altered soil porosity, bulk density, water holding capacity, microbial biomass carbon, substrate-induced respiration, alkaline phosphatase and fluorescein diacetate hydrolytic activities. Vegetable concentrations of heavy metal appeared in the order Zn > Pb > Cu > Ni > Cd and were maximum in leaves (spinach and amaranths) followed by fruits (tomato and egg plant) and minimum in roots (carrot and radish). Multiple regression analysis indicated that the major contribution of most heavy metals to vegetable leaves was from atmosphere. For roots however, soil appeared to be equally important. The study suggests that if the present trend of atmospheric deposition is continued, it will lead to a destabilizing effect on this sustainable agricultural practice and will increase the dietary intake of toxic metals.  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