全文获取类型
收费全文 | 161篇 |
免费 | 8篇 |
国内免费 | 21篇 |
专业分类
安全科学 | 33篇 |
环保管理 | 16篇 |
综合类 | 72篇 |
基础理论 | 37篇 |
环境理论 | 1篇 |
污染及防治 | 5篇 |
评价与监测 | 14篇 |
社会与环境 | 2篇 |
灾害及防治 | 10篇 |
出版年
2023年 | 7篇 |
2022年 | 8篇 |
2021年 | 11篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 2篇 |
2012年 | 5篇 |
2011年 | 16篇 |
2010年 | 9篇 |
2009年 | 26篇 |
2008年 | 8篇 |
2007年 | 9篇 |
2006年 | 10篇 |
2005年 | 7篇 |
2004年 | 7篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1993年 | 2篇 |
1990年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有190条查询结果,搜索用时 281 毫秒
171.
This study is about 16 policy-induced innovation networks on climate change adaptation, i.e., subsidised multi-actor networks that are initiated by research institutes and formed around a particular real-life problem aiming at joint development, test, and implement adaptation measures. The political-administrative context is Germany, and the institutional context is a joint research framework in which each network works independently on a particular topic, but remains bound to the principle of practical and solution-oriented research carried out in close partnership between scientific and extra-scientific actors. Our objective is to provide empirical insights into the processes and outcomes of such networks and to systematically analyse the networks’ collaboration success and its influencing factors. To this end, collaboration success is operationalised as a three-dimensional metric including (1) the practitioners’ satisfaction with the cooperation, (2) their perceived learning effects, and (3) their perceived implementation capacity. Results show a decreasing level of success throughout the three dimensions and particularly a gap between knowledge acquisition and learning on the one hand and implementation, i.e., transforming the knowledge into action, on the other. While the positive relationship between these dimensions is confirmed, results of correlation analysis highlight the importance of repeated participation, appropriate information management, and inclusive as well as responsive network practices. We discuss the results against our existing knowledge on multi-actor collaborative research and deduce (methodological) lessons learnt as well as future research needs. 相似文献
172.
昆仑山口西地震激发的地球环型振荡 总被引:7,自引:0,他引:7
利用中国数字地震台网(CDSN)改造后的7个台站3天的VHE、VHN波形资料,采用功率谱密度估计方法,在没有对资料进行去固体潮处理的情况下,提取了2001-11-14昆仑山口西地震激发的0T2~0T40地球环型自由振荡,并与地球初步参考模型(PREM)的理论自由振荡周期进行对比,发现环型振荡振型周期与PREM预测的环型自由振荡周期符合得很好。频率与PREM模型略微不一致的环型振荡振型可以解释为地球介质的横向不均匀性和各向异性所致。因此地球自由振荡信息可用于揭示地球的三维不均匀结构信息或各向异性信息,并可能对区分地幔对流模式(全地幔对流或上地幔对流)有所帮助。 相似文献
173.
L. Matamba C. Kazanci J.R. Schramski M. Blessing P. Alexander B.C. Patten 《Ecological modelling》2009,220(22):3174
Ecological network analysis (ENA), predicated on systems theory and Leontiev input–output analysis, is a method widely used in ecology to reveal ecosystem properties. An important ecosystem property computed in ENA is throughflows, the amount of matter/energy leaving each compartment of the ecosystem. Throughflows are analyzed via a matrix representing their relationships to the driving input at the boundary. Network particle tracking (NPT) builds on ENA to offer a Lagrangian particle method that describes the activity of the ecosystem at the microscopic level. This paper introduces a Lagrangian throughflow analysis methodology using NPT and shows that the NPT throughflow matrix, , agrees with the conventional ENA throughflow matrix, , for ecosystems at steady-state with donor-controlled flows. The matrix is computed solely from the pathways (particles’ histories) generated by NPT simulations and its average over multiple runs of the algorithm with longer simulation time agrees with the Eulerian matrix (Law of Large Numbers). While the traditional NEA throughflow analysis is mostly used with steady-state ecosystem models, the Lagrangian throughflow analysis that we propose can be used with non-steady-state models and paves the way for the development of dynamic throughflow analysis. 相似文献
174.
Daniel W. Franks Richard James Jason Noble Graeme D. Ruxton 《Behavioral ecology and sociobiology》2009,63(7):1079-1088
Researchers are increasingly turning to network theory to understand the social nature of animal populations. We present a
computational framework that is the first step in a series of works that will allow us to develop a quantitative methodology
of social network sampling to aid ecologists in their social network data collection. To develop our methodology, we need
to be able to generate networks from which to sample. Ideally, we need to perform a systematic study of sampling protocols on different known network structures, as network structure might affect the robustness of any
particular sampling methodology. Thus, we present a computational tool for generating network structures that have user-defined
distributions for network properties and for key measures of interest to ecologists. The user defines the values of these
measures and the tool will generate appropriate network randomizations with those properties. This tool will be used as a
framework for developing a sampling methodology, although we do not present a full methodology here. We describe the method
used by the tool, demonstrate its effectiveness, and discuss how the tool can now be utilized. We provide a proof-of-concept
example (using the assortativity measure) of how such networks can be used, along with a simulated egocentric sampling regime,
to test the level of equivalence of the sampled network to the actual network.
This contribution is part of the special issue “Social Networks: new perspectives” (Guest Editors: J. Krause, D. Lusseau and
R. James). 相似文献
175.
176.
The adaptive management leitmotiv of “learning to manage and managing to learn” sets out an attractive agenda for dealing
with the overwhelming complexity of environmental phenomena that humans have problematized. To ensure that this rallying cry
translates into effective action, it is important to give consideration to structures and procedures for facilitating the
efforts of those willing or able to respond to the adaptive management call. To date, calls to establish the right organization
to coordinate multiagency responses have tended to emphasize the noun, or bounded-entity, sense of the word organization.
We believe that this is at the expense of its other, verb or process, connotation. In this paper, rather than searching for
the perfect organization structure that mandates mutual trust and collective action shaped by all relevant parties' perspectives
and possible contributions, we direct attention towards the process of nurturing integrated adaptive responses among individuals
who have diverse organizational allegiances. By shifting the balance towards the process connotation of the right organization,
we hope that a new mindscape can be discerned for those interested in putting adaptive management principles into practice.
We seek to conjure up an image of this mindscape through the phrase “learning to network and networking to learn,” and set
out to strengthen this by demonstrating how adaptive response networks can arise from the mutually defining relationship between
stakeholders and issues. This is demonstrated through a local response to the United Kingdom's National Air Quality Strategy. 相似文献
177.
神经网络模型用于数值水质模型逼近的适用性及非敏感参数的欺骗效应 总被引:7,自引:2,他引:5
水质模型被广泛应用于水环境管理和决策,但却面临着计算时间和模型应用效率等多方面的问题;利用函数映射和逼近等方法来建立水质模型的输入-输出响应关系,可有效减少计算成本并显著改善模型效率.水质模型的输入-输出响应函数关系有多种形式,本文以其中的2种为例,并分别基于2个水质模型(零维总磷模型、WASP/EUTRO5)的案例,分析和验证了神经网络模型在响应关系逼近中的适用性.案例的结果表明:神经网络函数可以有效地用于水质模型输入-输出响应关系的逼近;当网络规模超出阈值大小时,神经网络函数逼近的准确度和泛化度对网络规模不敏感.在案例研究的基础上,推导和讨论了在神经网络模型函数映射过程中所可能出现的非敏感参数的欺骗效应,以及可能由此导致的过度预测或过低预测问题;并建议在神经网络函数逼近中,应只包含水质模型的敏感参数,以防止降低神经网络模型的准确度. 相似文献
178.
当前城市空气污染预报方法存在的问题及新思路 总被引:1,自引:1,他引:0
论述了当前国内外城市空气污染预报的主要方法以及存在的问题,探讨了一个基于贝叶斯网络的城市空气污染预报的新思路,并对其技术路线和关键问题等进行了初步探讨。新方法可以在一定程度上克服了现有方法理论上的缺陷和应用上的困难,而且具有更大的灵活性、现实性和可操作性,对于我国中小城市开展空气污染预报具有较好的应用前景。 相似文献
179.
Design of Mass Exchange Network and Effluent Distribution System for effective water management 总被引:1,自引:0,他引:1
The environmental impact of industrial wastewater and higher cost of fresh water are the serious challenges faced by the process industries. It has led to the development of many new techniques to minimize fresh water consumption. Of the many approaches, which have been developed, the Water Source Diagram (WSD) is a flexible and dynamic alternative for the generation of different scenarios for the management of water networks with reduction in total consumption. In the present study WSD concept was coupled with water mains concept to mains simplify the piping network and reduce the cost. A new procedure was developed for integrating the effluent treatment processes to evolve Effluent Treatment Network. Example from literature having multi contaminants was considered. This simple procedure involving hand calculations will be a useful tool for process engineers to design water and effluent treatment networks. Also the WSD and ETN were combined to form an evolutionary WAMEN (Water Allocation and Mass Exchange Network) and the proposed WAMEN aims for minimum fresh water consumption. 相似文献
180.
金沙江底栖真核微生物地理分布特征及生态学机制 总被引:1,自引:1,他引:0
真核微生物在生物地球化学循环、维持生态系统健康稳定等方面发挥重要作用.目前关于大型河流真核微生物的地理分布模式和生态学机制仍知之甚少.以我国西南梯级水电开发河流金沙江为研究区域,探讨了底栖真核微生物的地理分布特征及影响因素,解析了真核微生物的种间相互作用关系.结果表明,金沙江底栖真核微生物的α多样性指数沿河流向下表现出先上升后下降的趋势;群落结构和优势属的相对丰度在上游自然河段和梯级大坝河段差异显著.距离衰减分析的结果显示,金沙江底栖真核微生物的群落构建受环境筛选和扩散限制的共同作用;方差分解分析和中性模型的结果进一步表明,其地理分布模式主要受到扩散限制的驱动.共现网络结果表明,相比于上游自然河段,梯级大坝河段的种间竞争关系和网络联通性较弱,说明了底栖真核微生物在上游自然河段的相互作用更强.研究结果补充了我国西南河流底栖真核微生物多样性和地理分布的资料不足,为梯级水电开发河流底栖真核微生物的生态响应提供数据支撑. 相似文献