全文获取类型
收费全文 | 1518篇 |
免费 | 167篇 |
国内免费 | 340篇 |
专业分类
安全科学 | 88篇 |
废物处理 | 50篇 |
环保管理 | 328篇 |
综合类 | 890篇 |
基础理论 | 319篇 |
环境理论 | 4篇 |
污染及防治 | 108篇 |
评价与监测 | 31篇 |
社会与环境 | 190篇 |
灾害及防治 | 17篇 |
出版年
2024年 | 13篇 |
2023年 | 46篇 |
2022年 | 73篇 |
2021年 | 90篇 |
2020年 | 94篇 |
2019年 | 79篇 |
2018年 | 69篇 |
2017年 | 77篇 |
2016年 | 99篇 |
2015年 | 82篇 |
2014年 | 78篇 |
2013年 | 139篇 |
2012年 | 132篇 |
2011年 | 102篇 |
2010年 | 84篇 |
2009年 | 85篇 |
2008年 | 66篇 |
2007年 | 106篇 |
2006年 | 87篇 |
2005年 | 64篇 |
2004年 | 60篇 |
2003年 | 57篇 |
2002年 | 41篇 |
2001年 | 46篇 |
2000年 | 39篇 |
1999年 | 19篇 |
1998年 | 18篇 |
1997年 | 18篇 |
1996年 | 17篇 |
1995年 | 9篇 |
1994年 | 13篇 |
1993年 | 7篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有2025条查询结果,搜索用时 31 毫秒
991.
庆安县绿色食品产地环境质量预警研究 总被引:2,自引:0,他引:2
绿色食品产地环境质量预警是对自然变化、人类活动影响所引起的环境质量恶化进行预测,并及时提出警告.本文以国家级生态农业示范区庆安县的绿色食品产地为例,依据1993-2003年庆安县绿色食品产地环境质量监测数据及其状态转移矩阵,采用马尔可夫链模型预测未来5年环境质量状态发生概率,对该研究区进行环境质量负向演化预警研究.结果发出了巨宝村、东阳村和泥河农场的环境质量负向演化的预警信号.据此进行了警因分析并提出排警建议,为环境规划和管理部门提供科学治理依据和辅助决策. 相似文献
992.
产业园区是发展循环经济的重要载体,如何以企业为节点进行产业园区循环化改造,是国家发展循环经济的重点任务。基于循环经济理论的"减量化、再利用、再循环"原则,按照产业园区循环化改造可推广、可复制、可借鉴的要求,以武威黄羊工业园区为例,以其发展过程中存在的问题为依据,确定了循环化改造的主要任务,并就主导产业链进行了循环化改造,为农副产品加工园区的循环化改造提供一些借鉴。 相似文献
993.
Sarah Beganskas Robert J. Ryan Evelyn Walters Manahel Soro Elizabeth Cushman Laura Toran 《Journal of the American Water Resources Association》2021,57(1):134-153
We coupled rainfall–runoff and instream water quality models to evaluate total suspended solids (TSS) in Wissahickon Creek, a mid‐sized urban stream near Philadelphia, Pennsylvania. Using stormwater runoff and instream field data, we calibrated the model at a subdaily scale and focused on storm responses. We demonstrate that treating event mean concentrations as a calibration parameter rather than a fixed input can substantially improve model performance. Urban stormwater TSS concentrations vary widely in time and space and are difficult to represent simply. Suspended and deposited sediment pose independent stressors to stream biota and model results suggest that both currently impair stream health in Wissahickon Creek. Retrofitting existing detention basins to prioritize infiltration reduced instream TSS loads by 20%, suggesting that infiltration mitigates sediment more effectively than detention. Infiltrating stormwater from 30% of the watershed reduced instream TSS loads by 47% and cut the frequency of TSS exceeding 100 mg/L by half. Settled loads and the frequency of high TSS values were reduced by a smaller fraction than suspended loads and duration at high TSS values. A widely distributed network of infiltration‐focused projects is an effective stormwater management strategy to mitigate sediment stress. Coupling rainfall–runoff and water quality models is an important way to integrate watershed‐wide impacts and evaluate how management directly affects urban stream health. 相似文献
994.
M. A. Radwan K. S. El-Gendy A. F. Gad A. E. Khamis E. H. Eshra 《Chemistry and Ecology》2019,35(7):613-630
Silver nanoparticles (AgNPs) are now being of a great interest by ecotoxicological researchers. Their potential hazards to humans and other non-target organisms had led to crucial concerns. In this research, white radish leaf extract was used for the green synthesis of AgNPs. UV–Vis spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) have been utilised to characterise the biosynthesised AgNPs. Furthermore, the present study aimed to investigate the ecotoxicological effects of 1?mM biosynthesised AgNPs on the land snail, Theba pisana after two weeks of exposure and one week recovery with respect to oxidative stress parameters; lipid peroxidation (LPO), reduced glutathione (GSH), catalase (CAT) and glutathione-S-transferase (GST), cytogenetic parameters; DNA content and micronucleus test, as well as immunological parameters; cell death, phagocytosis, lysosomal membrane stability (LMS), lectins, superoxide anion (O2?) generation, phenoloxidase (PO), peroxidase (POD) and haemocyanin (Hc) were examined. AgNPs have been biosynthesised successfully; the UV–vis spectrum exhibited a single and broad absorption band located between 375 and 415?nm, TEM image shows AgNPs formed were nearly spherical in shape with a mean size of 2.18–19.87?nm and the crystalline nature of nanoparticles was confirmed by XRD. After two weeks exposure, the result showed that AgNPs significantly increased LPO level as well as CAT and GST activities, cell death, cell abnormalities and Hc level, whereas, significant decline was found in DNA and GSH contents, phagocytic activity, LMS, lectins, O2? generation, POD and PO activities compared to the controls. After a week of recovery, most of the tested biomarkers in AgNP-exposed snails did not completely return to the control levels. The multiple measured parameters could be effectively used as sensitive biomarkers in the risk assessment of contaminants in the terrestrial ecosystem. 相似文献
995.
Darfur farming and pastoralist livelihoods are both adaptations to the environmental variability that characterises the region. This article describes this adaptation and the longer‐term transformation of these specialised livelihoods from the perspective of local communities. Over several decades farmers and herders have experienced a continuous stream of climate, conflict and other shocks, which, combined with wider processes of change, have transformed livelihoods and undermined livelihood institutions. Their well‐rehearsed specialist strategies are now combined with new strategies to cope. These responses help people get by in the short term but risk antagonising not only their specialist strategies but also those of others. A combination of factors has undermined the former integration between farming and pastoralism and their livelihood institutions. Efforts to build resilience in similar contexts must take a long‐term view of livelihood adaptation as a specialisation, and consider the implications of new strategies for the continuity and integration of livelihood specialisations. 相似文献
996.
Software is a key factor in the functioning of today’s world. Software is supposed to have some characteristics such as: reliability, security, etc., but it is not at all easy to find energy efficiency considered as being one of software’s most important features. Aspects related to Green Software have begun to be considered vital and basic, due to pressure from a society which is becoming more and more aware of environmental problems. In this paper we want to explore whether software companies, responsible for developing software, are aligning their strategies with environmental concerns. To do so, we have checked the Corporate Social Responsibility (CSR) policies of the ten most important software companies and looked at these documents with reference to the UN’s sustainable development goals. A well-defined method for carrying out the analysis of the CSR policies led the authors to identify which of the sustainability actions proposed can be classified within any of the software sustainability dimensions. The analysis of these actions shows that sustainability is considered in most of the companies; nonetheless, most attention is currently devoted to hardware-based initiatives intended to reduce the carbon footprint of the hardware resources of the companies. In addition, green software initiatives are still not the priority, despite the influence of software on energy consumption, and in spite of its impact on the environment. Using the set of actions selected, a set of specific actions for software sustainability, to be included in the CSR of software companies, has been defined. 相似文献
997.
江西省矿产资源开发与环境保护 总被引:2,自引:0,他引:2
江西省矿产资源丰富,其开发利用有了很大发展,建成了具有一定生产规模和技术水平的有色金属、黑色金属、化工、建材、盐业、稀土稀有金属、煤炭等矿业体系.当前,由于多种因素的影响,导致矿山开采环境不断恶化,矿山地质灾害问题日趋严重,造成人员伤亡、环境破坏、矿产资源严重浪费.因此,我们应遵循"矿产资源开发利用与生态环境保护并重,预防为主与防治结合"的方针和"谁开发谁保护、谁污染谁治理、谁破坏谁恢复"的原则,强化矿山生态环境保护和恢复治理,走一条资源开发与环境保护相协调的矿业发展道路. 相似文献
998.
石化企业开展清洁生产的机会 总被引:1,自引:1,他引:1
以北京燕山石油化工公司生产现状分析和清洁生产审计实践为例,说明在生产管理,技术改造,原材料替代等方面,对于具有现代化装备的石化企业也存在着清洁生产的机会。 相似文献
999.
Paulo Petersen José Maria Tardin Francisco Marochi 《Environment, Development and Sustainability》1999,1(3-4):235-252
It is currently estimated that 40 million hectares worldwide are cultivated through no-tillage systems (Derpsh, 1998). Small family farms account for less than 50,000ha, half of them located in South America's Southern Cone (Wall, 1998). Many hypotheses have been offered to explain why so few small farmers have adapted to this method. The most simplistic ones relate this limited adoption to small farmers' traditionalism and to their rejection of innovation. Others point to the low technological development of animal-drawn equipment needed for this technology or the low educational level of family farmers.Results of work done in the Center-South of Paraná, Southern Brazil, by AS-PTA1 in partnership with the region's Forum of Family Farmers Organizations, challenge these hypotheses and draw attention to the need for new approaches and processes of research and extension if the goal is to disseminate and implement appropriate no-tillage systems among family farmers. One requisite is to lower production costs of this method through elimination of herbicides and using green manure and cover crops that shift the crop-weed balance in favor of crops. 相似文献
1000.