全文获取类型
收费全文 | 580篇 |
免费 | 3篇 |
国内免费 | 5篇 |
专业分类
安全科学 | 6篇 |
废物处理 | 37篇 |
环保管理 | 59篇 |
综合类 | 45篇 |
基础理论 | 135篇 |
污染及防治 | 167篇 |
评价与监测 | 111篇 |
社会与环境 | 27篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 16篇 |
2022年 | 50篇 |
2021年 | 32篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 19篇 |
2017年 | 14篇 |
2016年 | 29篇 |
2015年 | 17篇 |
2014年 | 28篇 |
2013年 | 58篇 |
2012年 | 27篇 |
2011年 | 32篇 |
2010年 | 35篇 |
2009年 | 23篇 |
2008年 | 33篇 |
2007年 | 27篇 |
2006年 | 22篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 13篇 |
2002年 | 15篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
1961年 | 3篇 |
1960年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有588条查询结果,搜索用时 31 毫秒
491.
Biodiversity conservation and management of natural resources are the best options to restore and increase productivity of
degrading pastureland in dry areas. Hence, arthropod abundance, organic matter, respiration, and dehydrogenase activity were
measured in canopy zone soil of Prosopis cineraria (PC), Acacia nilotica (AN), Zizyphus nummularia (ZN), Capparis decidua (CD), and Acacia senegal (AS) associated with grasses with a view to establish interrelation for productivity enhancement of pastureland. Pure grass
bock outside tree canopy was control plot. Acari, Myriapoda, Coleoptera, Isoptera, Collembola, and other soil arthropods were
the major soil faunal groups. Integration of tree in pastureland enhanced population of soil arthropod by 9–65-fold in May
2001 and 8–13-fold in August/September as compared with control. The trends of changes in soil organic matter (SOM), soil
respiration (SR), and dehydrogenase activity (DHA) were similar to the changes in soil arthropod population, indicating the
role of soil fauna in facilitating biochemical processes and soil fertility. Two, eight, and nine times greater SOM, SR, and
DHA, respectively, in silvipastoral system than the values in control suggest the beneficial effects of trees on improvement
in biochemical processes and thus biodiversity in pastureland, as supported by negative values of relative tree effects (RTE).
Microbial activities were highest in the ZN system, which had highest abundance of soil arthropods. In the other systems,
CD and AS systems showed greater soil arthropod abundance and biological activities than with the PC and AN systems. Therefore,
Z. nummularia-, C. decidua-, and A. senegal-based silvipastoral systems and related soil fauna may be promoted for enhancement of biological activity and productivity
of pastureland in desert. The strategy may be adopted for developing a sustainable pedoecosystem in a region of the world
where agriculture is notoriously difficult. 相似文献
492.
493.
Vinay Sharma J. S. Banait R. C. Larock P. P. Kundu 《Journal of Polymers and the Environment》2010,18(3):235-242
Linseed oil-based polymers have been synthesized via cationic and thermal polymerization and characterized through various
techniques, such as SEM, DMA, DSC and TGA. The morphology of the polymer samples after extraction reveals the smooth structure
of the polymer matrix. With an increase in oil content, the morphology is observed to be more loosely bound. With an increase
in linseed oil content in the samples, the room temperature storage modulus (E′) varies from 10.4 × 107 to 1.8 × 107 Pa. The glass transition temperatures measured through DMA of the cationic samples ranges from 70 to −6 °C and the crosslink
densities range from 18.4 × 103 to 3.4 × 103 mol/m3. The glass transition temperatures of the thermal samples range from 106 to −4 °C and the crosslink densities range from
7.7 × 103 to 2.4 × 103 mol/m3. The TGA results show three stages of degradation of the polymer samples and it is also revealed that these polymers are
stable up to 200 °C, showing negligible decomposition. 相似文献
494.
K. Michael A. Golab V. Shulakova J. Ennis-King G. Allinson S. Sharma T. Aiken 《International Journal of Greenhouse Gas Control》2010,4(4):659-667
The experience from CO2 injection at pilot projects (Frio, Ketzin, Nagaoka, US Regional Partnerships) and existing commercial operations (Sleipner, Snøhvit, In Salah, acid-gas injection) demonstrates that CO2 geological storage in saline aquifers is technologically feasible. Monitoring and verification technologies have been tested and demonstrated to detect and track the CO2 plume in different subsurface geological environments. By the end of 2008, approximately 20 Mt of CO2 had been successfully injected into saline aquifers by existing operations. Currently, the highest injection rate and total storage volume for a single storage operation are approximately 1 Mt CO2/year and 25 Mt, respectively. If carbon capture and storage (CCS) is to be an effective option for decreasing greenhouse gas emissions, commercial-scale storage operations will require orders of magnitude larger storage capacity than accessed by the existing sites. As a result, new demonstration projects will need to develop and test injection strategies that consider multiple injection wells and the optimisation of the usage of storage space. To accelerate large-scale CCS deployment, demonstration projects should be selected that can be readily employed for commercial use; i.e. projects that fully integrate the capture, transport and storage processes at an industrial emissions source. 相似文献
495.
A methodology is developed for estimating the number of waste sorts for characterizing solid wastes into categories based on diminishing minimum incremental information. Convergence in the square of the coefficient of variation with successive waste sorts is used to indicate cost-efficient termination of sampling at substantially reduced numbers of sorts in comparison with existing methodologies. These findings indicate that the numbers of waste sorts beyond that determined using the proposed methodology do not add substantial marginal gains in information and/or reduction in the confidence interval of the estimate. The methodology is demonstrated using waste composition analyses from the Greater Vancouver Regional District where 22 waste sorts are examined. The proposed methodology is simple, and the number of waste sorts can be estimated with a hand-held calculator and utilized in the field. 相似文献
496.
Vethamony P Sudheesh K Babu MT Jayakumar S Manimurali R Saran AK Sharma LH Rajan B Srivastava M 《Environmental pollution (Barking, Essex : 1987)》2007,148(2):438-444
An oil spill occurred off Goa, west coast of India, on 23 March 2005 due to collision of two vessels. In general, fair weather with weak winds prevails along the west coast of India during March. In that case, the spill would have moved slowly and reached the coast. However, in 2005 when this event occurred, relatively stronger winds prevailed, and these winds forced the spill to move away from the coast. The spill trajectory was dominated by winds rather than currents. The MIKE21 Spill Analysis model was used to simulate the spill trajectory. The observed spill trajectory and the slick area were in agreement with the model simulations. The present study illustrates the importance of having pre-validated trajectories of spill scenarios for selecting eco-sensitive regions for preparedness and planning suitable response strategies whenever spill episodes occur. 相似文献
497.
Singh KP Singh VK Malik A Sharma N Murthy RC Kumar R 《Environmental monitoring and assessment》2007,131(1-3):237-254
Rain water samples were collected to study the chemical composition of wet atmospheric precipitation (first event) over the
Lucknow city in the northern Indo-gangetic alluvial plains. The samples were collected in the month of July, 2005 from different
sites. The wet precipitation samples were analyzed for pH, EC, major ions (, Cl−, , , , F−, Na+, K+, Ca2+, Mg2+, ) and heavy metals (As, Cd, Al, Co, Cr, Cu, Fe, Mn, Mo, Ni, Hg, Pb, Se, Sn, Ti, V, Zn). The pH values of wet precipitation
samples ranged between 6.5 and 8.7. The analysis of linear regression applied to the set of studied variables and computation
of neutralization factors showed that neutralization occurred in precipitation samples and Ca2+ had the maximum neutralization capacity. It was found that Cl−, , Ca2+, Mg2+, Na+ and K+ in the precipitation samples originated mainly from crustal/anthropogenic sources in the region. On an average Fe, and Al
accounted for >72% of the total concentration of trace metals in the wet precipitation samples followed by Zn (>10%). Enrichment
factors calculated for heavy metals over reference background level in seawater and Earth’s crust showed relatively higher
enrichment of Zn. The principal component analysis (PCA) identified the possible sources of ionic species and heavy metals
in the wet precipitation samples. 相似文献
498.
Residues dynamics of Endosulfan (525.00 g a.i. ha(-1)), Imidacloprid seed treatment (21 g a.i. kg(-1)), Lambdacyhalothrin (75.00 g a.i. ha(-1)) and Spiromesifen (225.00 g a.i. ha(-1)) in nectar and pollen of mustard, Brassica juncea (L.) Czern. grown in Himachal Pradesh (India) were determined through bioassay (using Drosophila melanogaster Meig. as test organism) and GC (Gas chromatographic) and HPLC (High performance liquid chromatographic) methods. In general chromatographic methods were more sensitive for the determination of above given pesticides compared to bioassay method. Average recoveries in nectar samples varied between 82.85 and 88.90% by bioassay and 91.20 and 93.55% by chromatographic techniques. In pollen samples, recoveries varied between 81.44 and 86.44% by bioassay and 88.50 and 91.30% by chromatographic methods. Imidacloprid residues were neither found in nectar nor in pollen samples at the time of sampling i.e. 50% of flowering. The order of average half life of residues was: Lambdacyhalothrin (12.45 h) < Spiromesifen (19.99 h) < Endosulfan (27.49 h) for nectar and Spiromesifen (9.69 h) < Lambdacyhalothrin (12.44 h) < Endosulfan (17.84 h) for pollen samples. It was found that Imidcloprid seed treatment was practically harmless to honey bees, whereas a waiting period of 5 days must be observed on crops sprayed with these chemicals during blooms to avoid any accidental hazards to honey bees. 相似文献
499.
Road sides provide suitable conditions for the establishment and growth of non-native species. The phenomenon of non-native species spread through roads has further increased due to rapid anthropogenic developments. Here we intend to investigate the status of native and non-native species and how the species richness and diversity change in a perpendicular road transect across the three different road use types in the central highlands of India. Presence of 55 non-native species was recorded, of the total 71 species along the road sides. Non-native species richness significantly increased with increasing road use type. Although, the species diversity significantly decreased from road verges to the forest interior in all the road use types. Indicating the role of non-native propagule spread through the roads into the interior forest landscapes. The study gives a management implication, to restrict the non-native species spread from the road sides to the forest interior, irrespective of road use types. 相似文献
500.
Indu Chopra Beena Kumari S. K. Sharma 《Environmental monitoring and assessment》2010,160(1-4):123-126
The mobility of pendimethalin in sandy loam soil was studied in soil columns under laboratory conditions at two application rates, 1.0 and 2.0 kg a.i. ha???1, with simulated rainfall of 300 mm. The maximum concentration of the herbicide was found in the top 10 cm layer, though it was found distributed in soil at all the depths at both the doses. 相似文献