全文获取类型
收费全文 | 1294篇 |
免费 | 55篇 |
国内免费 | 466篇 |
专业分类
安全科学 | 74篇 |
废物处理 | 79篇 |
环保管理 | 80篇 |
综合类 | 730篇 |
基础理论 | 220篇 |
污染及防治 | 510篇 |
评价与监测 | 46篇 |
社会与环境 | 45篇 |
灾害及防治 | 31篇 |
出版年
2023年 | 26篇 |
2022年 | 72篇 |
2021年 | 76篇 |
2020年 | 34篇 |
2019年 | 44篇 |
2018年 | 48篇 |
2017年 | 62篇 |
2016年 | 62篇 |
2015年 | 66篇 |
2014年 | 107篇 |
2013年 | 110篇 |
2012年 | 96篇 |
2011年 | 120篇 |
2010年 | 80篇 |
2009年 | 94篇 |
2008年 | 96篇 |
2007年 | 86篇 |
2006年 | 59篇 |
2005年 | 46篇 |
2004年 | 47篇 |
2003年 | 47篇 |
2002年 | 26篇 |
2001年 | 39篇 |
2000年 | 41篇 |
1999年 | 35篇 |
1998年 | 34篇 |
1997年 | 24篇 |
1996年 | 25篇 |
1995年 | 19篇 |
1994年 | 15篇 |
1993年 | 16篇 |
1992年 | 8篇 |
1991年 | 16篇 |
1990年 | 15篇 |
1989年 | 6篇 |
1988年 | 10篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有1815条查询结果,搜索用时 636 毫秒
651.
煤中氟化物在燃烧产物中的分布特征 总被引:5,自引:0,他引:5
通过煤的灰化程序研究煤中氟在燃烧产物中的静态分布特征,并对不同燃烧方式的工业和电站锅炉燃烧时煤中氟化物在燃烧产物中的分布特征进行试验结果表明:煤中氟属于强挥发性元素,在煤灰中是非浓集的.煤粉炉燃煤过程中,煤中氟析出强度高,约有94.5%的氟以气态氟形式析出;层燃炉气态氟的析出率略有降低,约有80%的氟以气态氟形式析出.煤粉炉飞灰各级分粒子中氟元素的质量分数分布呈"单峰"型,峰值出现在74~104μm粒度级,约占飞灰总氟量的55%~60%. 相似文献
652.
Luyu Ding Qikun Lu Lina Xie Jie Liu Wei Cao Zhengxiang Shi 《Journal of the Air & Waste Management Association (1995)》2016,66(3):267-279
The open lots and manure stockpiles of dairy farm are major sources of greenhouse gas (GHG) emissions in typical dairy cow housing and manure management system in China. GHG (CO2, CH4 and N2O) emissions from the ground level of brick-paved open lots and uncovered manure stockpiles were estimated according to the field measurements of a typical dairy farm in Beijing by closed chambers in four consecutive seasons. Location variation and manure removal strategy impacts were assessed on GHG emissions from the open lots. Estimated CO2, CH4 and N2O emissions from the ground level of the open lots were 137.5±64.7 kg hd-1 yr-1, 0.45±0.21 kg hd-1 yr-1 and 0.13±0.08 kg hd-1 yr-1, respectively. There were remarkable location variations of GHG emissions from different zones (cubicle zone vs. aisle zone) of the open lot. However, the emissions from the whole open lot were less affected by the locations. After manure removal, lower CH4 but higher N2O emitted from the open lot. Estimated CO2, CH4 and N2O emissions from stockpile with a stacking height of 55±12 cm were 858.9±375.8 kg hd-1 yr-1, 8.5±5.4 kg hd-1 yr-1 and 2.3±1.1 kg hd-1 yr-1, respectively. In situ storage duration, which estimated by manure volatile solid contents (VS), would affect GHG emissions from stockpiles. Much higher N2O was emitted from stockpiles in summer due to longer manure storage.Implications: This study deals with greenhouse gas (GHG) emissions from open lots and stockpiles. It’s an increasing area of concern in some livestock producing countries. The Intergovernmental Panel on Climate Change (IPCC) methodology is commonly used for estimation of national GHG emission inventories. There is a shortage of on-farm information to evaluate the accuracy of these equations and default emission factors. This work provides valuable information for improving accounting practices within China or for similar manure management practice in other countries. 相似文献
653.
Adverse consequences to the ecological system and human health caused by impacts potentially attributable to climate change have already drawn great and widespread concern of many scientists and international organizations. However, we still have a hard time determining exactly the impact of climate change on the environment or the damage that climate change inflicts on countries comprising small islands or low-lying lands in light of today’s science and technology. The progress for dealing with the issue of loss and damage has been struggling for a long time from the beginning to the present. In this paper, the author begins by summarizing talks on the concept and the positions of commentators. The author is proposing that the development of future climate negotiations and rule-making process be based on global climate justice as a standard for measuring value. Also, the author proposes that a holistic view of climate justice be established. Generally, three aspects of climate justice can be derived. First, the dimension of human rights protection shows that protection of fundamental human rights is a logical precondition if small-island and low-lying countries are able to achieve climate justice. Second, the definite and traditional concepts of distributive justice and corrective justice hold the view that the principle of common but differentiated responsibilities should be upheld as a basic standard of allocating rights and duties associated with climate change. Third, climate justice requires that any state follow the “no-harm principle,” which is regarded as an international customary rule. According to the principle, the obligation of states to prevent the use of their territory for causing trans-boundary harm to the environment shall be a violation of state responsibility, which incurs international punishment. Then we put forward three remedial approaches in light of climate justice, including the approach of State Responsibility (SR) based on the principles and rules of international human rights law and international environmental law. Based on clear rules, the judge can determine whether the damaging behavior or the damage perpetrated by a state party constitutes a state responsibility. The International Environmental Regulation (IEB), which means solving the problems within the framework established by the Conventions on Climate Change, takes advantage of the market mechanisms and incentives such as fund and insurance support system to relieve or compensate the loss and damage. International Environmental Dispute Settlement Mechanism (IEDSM), which includes the means such as consultations, negotiations, nonmandatory ways and international arbitration, international judicial ways to solve these disputes, functions as a procedural safeguard. As an active promoter of global climate governance, China should no doubt stand by the principle of Common But Differentiated Responsibility (CBDR) and take it as a basis for negotiations, actively strengthen the work of South-South cooperation, fulfill her international climate commitments without reservation, vigorously develop a low-carbon economy, and actively promote international negotiations on the subject of loss and damage. 相似文献
654.
China has among the highest biodiversities in the world, but faces extreme biodiversity losses due to the country’s huge population and its recent explosive socioeconomic development. Despite huge efforts and investments by the government and Chinese society to conserve biodiversity, especially in recent decades, biodiversity losses may not have been reversed, and may even have been exacerbated by unintended consequences resulting from these projects. China’s centralized approach to biodiversity conservation, with limited local participation, creates an inflexible and inefficient approach because of conflicts between local communities and national administrators over the benefits. Although community-based conservation may be an imperfect approach, it is an essential component of a successful future national conservation plan. Biodiversity conservation should be considered from the perspective of systems engineering and a governance structure that combines centralization with community-level conservation. In this paper, we describe China’s complex challenge: how to manage interactions between humans and nature to find win–win solutions that can ensure long-term biodiversity conservation without sacrificing human concerns. 相似文献
655.
以共沉淀法制备纳米Fe3O4,通过分散聚合法制备了磁性聚(苯乙烯-甲基丙烯酸)(Fe3O4@P(St-MMA))微球,采用光学显微镜、红外光谱、样品磁力振荡计和X射线衍射(XRD)对磁性微球进行了表征。考察了复合磁性微球在不同的p H、离子强度和吸附时间等条件下对其吸附性能的影响,运用吸附动力学和吸附等温线研究了磁性微球对亚甲基蓝的表面吸附机理。结果表明,制备的磁性微球粒径在100~200μm之间,表面含有羧基,饱和磁化强度为9.44 emu/g,在外加磁场的作用下能够快速分离出来。亚甲基蓝的吸附符合准二级动力学模型,在100 min内基本达到吸附平衡;25℃下,最大吸附量高达144.9 mg/g,且吸附随着p H值的升高而增加,当p H7时,吸附量基本不变;随着离子强度增加,吸附量逐渐下降;Langmuir等温线能比较好地拟合磁性微球对溶液中亚甲基蓝的吸附。 相似文献
656.
657.
以稀土元素(简称稀土)用量较大的废FCC催化剂和废汽车尾气净化催化剂为研究对象,分析总结了两类废催化剂中稀土的成分和回收方法。从废催化剂中回收稀土普遍采用先浸出、后分离提纯的方法。浸出普遍采用无机酸(多为盐酸),分离方法包括溶剂萃取法、化学沉淀法等,最后经焙烧得到稀土氧化物。为从废催化剂中高效回收稀土,可着重考察新浸出机制的引入、分离方式的选择、分离试剂的应用,以及浸出和分离条件的优化,从而为实现工业化回收提供技术支持。 相似文献
658.
Hao Yu Zhan Chen He Shang Jixin Cao 《Environmental science and pollution research international》2017,24(21):17418-17427
Considerable researches have documented the negative effects of ozone on woody species in North America and Europe; however, little is known about how woody tree species respond to elevated O3 in subtropical China, and most of the previous studies were conducted using pot experiment. In the present study, Machilus ichangensis Rehd. et Wils (M. ichangensis) and Taxus chinensis (Pilger) Rehd. (T. chinensis), evergreen tree species in subtropical China, were exposed to non-filtered air (NF), 100 nmol mol?1 O3 (E1) and 150 nmol mol?1 O3 (E2), in open-top chambers under field conditions from 21st March to 2nd November 2015. In this study, O3 fumigation significantly reduced net photosynthesis rate (Pn) in M. ichangensis in the three measurements and in T. chinensis in the last measurement. Also, non-stomatal factors should be primarily responsible for the decreased Pn. O3 fumigation-induced increase in malondialdehyde, superoxide dismutase, and reduced ascorbic acid levels indicated that antioxidant defense mechanism had been stimulated to prevent O3 stress and repair the oxidative damage. Yet, the increase of antioxidant ability was not enough to counteract the harm of O3 fumigation. Because of the decrease in CO2 assimilation, the growth of the two tree species was restrained ultimately. The sensitivity of the two tree species to O3 can be determined: M. ichangensis > T. chinensis. It suggests a close link between the rising O3 concentrations and the health risk of some tree species in subtropics in the near future. 相似文献
659.
利用生物毒性测试对环境中的污染物进行生态风险评价,是目前风险评价中的研究热点。本研究以明亮发光杆菌(Photobacterium phosphoreum)、斜生栅藻(Scenedesmus obliquus)和大型溞(Daphina magna)为受试生物,对某石化厂废水的处理流程中5个主要单元出水的急性毒性进行了测试,分析了其急性毒性与理化指标间的相关性;同时,为了解不同处理单元毒性去除效果及主要毒性来源,结合毒性鉴别评价(toxicity identification evaluation,TIE)技术对各阶段出水的毒性削减及其主要致毒物质类别进行了分析。毒性测试结果表明,该废水处理厂对石化废水的毒性去除效果比较显著,其中进水对明亮发光杆菌、斜生栅藻和大型溞分别表现为中毒、高毒和剧毒,最终处理后出水的毒性分别为无急性毒、中毒和微毒,对毒性的去除效率分别为96.4%、74.3%和99.5%。TIE结果表明,石化废水中的主要致毒物质是非极性有机物和可滤型物质。本研究结果为石化废水的综合生物毒性评价提供了研究基础,为探讨废水生物毒性的去除提供了实例参考。 相似文献
660.