全文获取类型
收费全文 | 1070篇 |
免费 | 45篇 |
国内免费 | 335篇 |
专业分类
安全科学 | 62篇 |
废物处理 | 63篇 |
环保管理 | 89篇 |
综合类 | 539篇 |
基础理论 | 193篇 |
污染及防治 | 361篇 |
评价与监测 | 49篇 |
社会与环境 | 32篇 |
灾害及防治 | 62篇 |
出版年
2023年 | 17篇 |
2022年 | 59篇 |
2021年 | 43篇 |
2020年 | 27篇 |
2019年 | 30篇 |
2018年 | 40篇 |
2017年 | 42篇 |
2016年 | 41篇 |
2015年 | 59篇 |
2014年 | 81篇 |
2013年 | 102篇 |
2012年 | 98篇 |
2011年 | 95篇 |
2010年 | 78篇 |
2009年 | 65篇 |
2008年 | 79篇 |
2007年 | 69篇 |
2006年 | 74篇 |
2005年 | 47篇 |
2004年 | 31篇 |
2003年 | 32篇 |
2002年 | 32篇 |
2001年 | 29篇 |
2000年 | 22篇 |
1999年 | 21篇 |
1998年 | 22篇 |
1997年 | 23篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有1450条查询结果,搜索用时 763 毫秒
841.
842.
Györgyi Bela Taru Peltola Juliette C. Young Bálint Balázs Isabelle Arpin György Pataki Jennifer Hauck Eszter Kelemen Leena Kopperoinen Ann Van Herzele Hans Keune Susanne Hecker Monika Suškevičs Helen E. Roy Pekka Itkonen Mart Külvik Miklós László Corina Basnou Joan Pino Aletta Bonn 《Conservation biology》2016,30(5):990-999
The number of collaborative initiatives between scientists and volunteers (i.e., citizen science) is increasing across many research fields. The promise of societal transformation together with scientific breakthroughs contributes to the current popularity of citizen science (CS) in the policy domain. We examined the transformative capacity of citizen science in particular learning through environmental CS as conservation tool. We reviewed the CS and social‐learning literature and examined 14 conservation projects across Europe that involved collaborative CS. We also developed a template that can be used to explore learning arrangements (i.e., learning events and materials) in CS projects and to explain how the desired outcomes can be achieved through CS learning. We found that recent studies aiming to define CS for analytical purposes often fail to improve the conceptual clarity of CS; CS programs may have transformative potential, especially for the development of individual skills, but such transformation is not necessarily occurring at the organizational and institutional levels; empirical evidence on simple learning outcomes, but the assertion of transformative effects of CS learning is often based on assumptions rather than empirical observation; and it is unanimous that learning in CS is considered important, but in practice it often goes unreported or unevaluated. In conclusion, we point to the need for reliable and transparent measurement of transformative effects for democratization of knowledge production. 相似文献
843.
844.
845.
Su Y Hung H Stern G Sverko E Lao R Barresi E Rosenberg B Fellin P Li H Xiao H 《Journal of environmental monitoring : JEM》2011,13(11):3111-3118
Initiated in 1992, air monitoring of organic pollutants in the Canadian Arctic provided spatial and temporal trends in support of Canada's participation in the Stockholm Convention of Persistent Organic Pollutants. The specific analytical laboratory charged with this task was changed in 2002 while field sampling protocols remained unchanged. Three rounds of intensive comparison studies were conducted in 2004, 2005, and 2008 to assess data comparability between the two laboratories. Analysis was compared for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in standards, blind samples of mixed standards and extracts of real air samples. Good measurement accuracy was achieved for both laboratories when standards were analyzed. Variation of measurement accuracy over time was found for some OCPs and PCBs in standards on a random and non-systematic manner. Relatively low accuracy in analyzing blind samples was likely related to the process of sample purification. Inter-laboratory measurement differences for standards (<30%) and samples (<70%) were generally less than or comparable to those reported in a previous inter-laboratory study with 21 participating laboratories. Regression analysis showed inconsistent data comparability between the two laboratories during the initial stages of the study. These inter-laboratory differences can complicate abilities to discern long-term trends of pollutants in a given sampling site. It is advisable to maintain long-term measurements with minimal changes in sample analysis. 相似文献
846.
Xia D He C Zhu L Huang Y Dong H Su M Asi MA Bian D 《Journal of environmental monitoring : JEM》2011,13(4):864-870
The objective of this work was to develop a novel wet-scrubbing process using Fe(VI) for the simultaneous removal of gaseous NO and SO(2). The oxidation of SO(2) and NO with Fe(VI) was studied in aqueous solution at alkaline pH (9.0-11.0). A stoichiometric molar ratio for NO and SO(2) oxidation with Fe(VI) was determined to be nearly 3.0. Sulfate and nitrate was identified as final products by ion chromatography from the reaction at pH 9.0-11.0. The feasibility of simultaneous removal of multiple gas pollutants with the continuous feeding of ferrate in lab-scale was investigated from the view of industrial application. It was found that the removal efficiency of NO and SO(2) was enhanced with the increase of Fe(VI) concentration, more than 90% NO removal efficiency and 100% SO(2) removal efficiency were achieved by wet-scrubbing process using Fe(VI) at room temperature and ambient atmosphere. The results demonstrate that Fe(VI) could be an effective wet-scrubbing agent for the simultaneous removal of NO and SO(2). 相似文献
847.
苏健 《中国个体防护装备》2011,(2):24-26
本文主要介绍新标准GB19083-2010的修订背景、新旧标准的差异对比,重点介绍影响口罩防护效果的重要指标—过滤效率和口罩密合性项目,并对生产厂家在应用标准时需要注意的事项加以说明。 相似文献
848.
为了给人工强化生态滤床在工程应用选择滤料提供参考,利用室内模拟试验装置,考察了沸石、砾石、火山岩、陶环、碳环5种滤料在孔隙率、挂膜速度、机械强度、不同进水流量条件下COD、氨氮去除效果等方面的性能.结果表明,陶环和碳环孔隙率远大于其他3种滤料,陶环、碳环.火山岩.沸石和砾石的孔隙率分别为77%,75%,47%,38%和35%.当水力负荷为8mL/min时,在第11d,砾石滤料和火山岩滤料的COD去除率稳定,分别达到40.8%和41.6%,而其他3种滤料去除率仍处于上升阶段.这说明砾石与火山岩挂膜速度大于其他3种滤料.当系统稳定运行后,在水力负荷为3.75 mL/min时,碳环和火山岩滤料的COD去除率高于其他3种滤科.当水力负荷保持3.75mL/min时,进水COD升高,火山岩滤料COD去除率降低,小于其他3种滤料.这说明火山岩滤料与其他滤料相比具有更好的抗COD负荷冲击能力.沸石抗氨氮负荷冲击能力高于其他滤料.陶环和碳环强度差于其他3种滤料.研究表明,5种滤料各具特点,在实际工程滤料选择过程中应充分考虑施工和造价等因素.对于大型工程,如果工程当地不具备火出岩和沸石矿资源,应优先选择砾石滤料. 相似文献
849.
Seung Min LeeJun Su Ha Poong Hyun Seong 《Journal of Loss Prevention in the Process Industries》2011,24(1):90-97
Communication error has been considered a primary cause of many incidents and accidents in the nuclear industry. In order to prevent these accidents, a method for the analysis of such communication errors is proposed here. This paper presents a qualitative and a quantitative method to analyze communication errors. The qualitative method focuses on finding a root cause of the communication error and predicting the type of communication error which could happen in nuclear power plants. We develop context conditions and antecedent-consequent links of influential factors related to communication errors. The quantitative analysis method focuses on estimating the probability of communication errors. To accomplish the quantification of communication errors, the Cognitive Speaking Process (CSP) is defined and a method to estimate the weighting factors and the probability is suggested. Finally, case studies conducted to validate the applicability of the proposed methods are detailed. From the results, we can foresee the effects of given plant conditions on communication errors and reduce the error occurrences. 相似文献
850.
水环境健康风险评价在参数确定、暴露评估与风险表征过程中存在着不确定性因素,利用随机模拟与三角模糊数耦合模型(SS-TFN模型)进行水环境健康风险评价,降低了评价过程中人为因素的影响,有效提高评价结果的可靠性和科学性.本文将SS-TFN模型应用于盘锦市六个饮用水源地致癌物质经饮水途径的地下水环境健康风险评价中,结果表明:盘锦市六个饮用水源地的总致癌风险均超过致癌年风险率控制限值(1.0&#215;10-5);致癌物质造成的平均个人致癌年风险率由高到低排序:Cr6+> As> Cd.盘锦市六个饮用水源地SS-TFN计算结果收敛时总的平均个人致癌年风险由高到低排列:大洼水源>兴南水源>兴一水源>盘东水源>高升水源>石山水源. 相似文献