全文获取类型
收费全文 | 5889篇 |
免费 | 43篇 |
国内免费 | 22篇 |
专业分类
安全科学 | 137篇 |
废物处理 | 223篇 |
环保管理 | 339篇 |
综合类 | 1755篇 |
基础理论 | 1319篇 |
环境理论 | 9篇 |
污染及防治 | 1547篇 |
评价与监测 | 326篇 |
社会与环境 | 289篇 |
灾害及防治 | 10篇 |
出版年
2022年 | 65篇 |
2021年 | 64篇 |
2020年 | 47篇 |
2019年 | 59篇 |
2018年 | 177篇 |
2017年 | 171篇 |
2016年 | 204篇 |
2015年 | 149篇 |
2014年 | 186篇 |
2013年 | 311篇 |
2012年 | 202篇 |
2011年 | 320篇 |
2010年 | 208篇 |
2009年 | 203篇 |
2008年 | 311篇 |
2007年 | 265篇 |
2006年 | 229篇 |
2005年 | 180篇 |
2004年 | 164篇 |
2003年 | 142篇 |
2002年 | 168篇 |
2001年 | 106篇 |
2000年 | 88篇 |
1999年 | 66篇 |
1998年 | 47篇 |
1997年 | 43篇 |
1996年 | 54篇 |
1995年 | 56篇 |
1994年 | 54篇 |
1993年 | 40篇 |
1992年 | 48篇 |
1991年 | 46篇 |
1990年 | 40篇 |
1989年 | 35篇 |
1988年 | 34篇 |
1981年 | 34篇 |
1976年 | 35篇 |
1967年 | 34篇 |
1966年 | 33篇 |
1965年 | 49篇 |
1964年 | 41篇 |
1963年 | 38篇 |
1961年 | 46篇 |
1960年 | 41篇 |
1959年 | 43篇 |
1958年 | 46篇 |
1957年 | 40篇 |
1956年 | 40篇 |
1955年 | 38篇 |
1954年 | 42篇 |
排序方式: 共有5954条查询结果,搜索用时 625 毫秒
391.
Marco Inés Padró Roc Cattaneo Claudio Caravaca Jonathan Tello Enric 《Regional Environmental Change》2018,18(4):981-993
Regional Environmental Change - We analyse the changes to agricultural metabolism in four municipalities of Vallès County (Catalonia, Iberia) by accounting for their agroecosystem funds and... 相似文献
392.
Lars Löfquist 《Disasters》2017,41(1):41-54
This paper analyses the contribution of virtue ethics, the study of good character traits, to the humanitarian context. It argues that a virtue ethics perspective paints a realistic picture of the use of ethical standards in morally complex circumstances. Virtuous relief workers can employ standards in their thinking, but they are also committed to professional excellence that goes beyond any formal code. The concept of virtue ethics places a stress on moral development, which can be facilitated by role models that impart modest and feasible ideals. However, virtue ethics cannot provide simple guidelines on how to resolve difficult situations. It is possible that two virtuous persons can disagree on what should be done in a particular instance. In addition, a virtue ethics perspective emphasises the need for both individuals and organisations to discuss the actual purpose of relief work in order to pinpoint the virtues of a good relief professional. 相似文献
393.
The humanitarian common logistic operating picture: a solution to the inter‐agency coordination challenge
下载免费PDF全文
![点击此处可从《Disasters》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Although significant progress has been made in developing the practice of humanitarian logistics, further improvements in efficiency and effectiveness have the potential to save lives and reduce suffering. This paper explores how the military/emergency services’ concept of a common operating picture (COP) can be adapted to the humanitarian logistics context, and analyses a practical and proven approach to addressing the key challenge of inter‐agency coordination and decision‐making. Successful adaptation could provide the mechanism through which predicted and actual demands, together with the location and status of material in transit, are captured, evaluated, and presented in real time as the basis for enhanced decision‐making between actors in the humanitarian supply network. Through the introduction of a humanitarian logistics COP and its linkages to national disaster management systems, local communities and countries affected by disasters and emergencies will be better placed to oversee and manage their response activities. 相似文献
394.
Manuel Vonrüti Aleksandar Spasojevic Nils Nölke Thomas Kneib Christoph Kleinn 《Environmental and Ecological Statistics》2017,24(3):385-398
Temperature is an important physical factor that is known to strongly affect biodiversity as well as ecosystems and their functioning. However, research in this area is still relatively limited; this may also be attributed to the multitude of influencing factors and the complexity of the statistics involved. This study analyzes the differences between the surface temperature of three Central European broadleaf tree species. A better understanding of these differences may help to elucidate the role of microclimate in biodiversity. We consider a time series of high-resolution thermal images taken from a meteorological observation tower and calculate mean canopy leaf temperatures for beech, ash and maple (Fagus silvatica, Fraxinus excelsior and Acer pseudoplatanus). In a first step, comparable image areas are extracted from the thermal image sections of the crown of each tree species avoiding shadow areas, branches, etc. We used an automatic segmentation technique, the Otsu thresholding. Extracted canopy leaf temperature values were then processed and the resulting temperature profiles estimated by O’Sullivan penalized splines. For comparing the differences in canopy leaf temperature over time, we propose the construction of simultaneous confidence bands. The analyses show that there are significant—though small—differences in canopy surface temperature between the three tree species. 相似文献
395.
P.?AngelidisEmail authorView authors OrcID profile D.?Kalpakis V.?Gyrikis N.?Kotsovinos 《Environmental Fluid Mechanics》2017,17(3):615-628
We consider the problem of the vertically upwards disposal of heavy brine sewage from a two-dimensional diffuser in a lighter, homogeneous, motionless and shallow ambient sea. The rejected high salinity water of seawater desalination plants for urban and agricultural uses is such a case of a two dimensional fountain. The disposal of brine sewage produces a negative buoyant jet due to its initial momentum, which impinges on the free surface, spreads laterally on it and then sinks downwards, because of the negative buoyancy. Laboratory experiments and dimensional considerations are used in this paper in order to investigate the spreading behavior (width) of the vertical fountain which impinges on the free surface of the shallow ambient fluid. The experimental results have been used to derive an equation relating the width at the free surface with the initial parameters of the flow. In addition, the experimentally measured dilution of the heavier brine sewage on the recipient’s surface is compared with the dilution which was calculated by a numerical simulation of a well-known commercial software package, CORJET (a CORMIX sub model). 相似文献
396.
Ting?ZhangEmail authorView authors OrcID profile Fangxin?Fang Ping?Feng 《Environmental Fluid Mechanics》2017,17(5):959-979
Dam failures usually cause huge economic and life losses , especially in urban areas where there is a high concentration of inhabitants and economic actors. In order to understand the physical mechanisms of the formation and development of dam-break flooding, lots of efforts have been put into different types of modelling techniques. However, most of existing models are 1D (one-dimensional) or 2D models based on the shallow water equations. In this paper, we present a 3D numerical modelling investigation of dam-break flow hydrodynamics in an open L-shape channel. A newly developed 3D unstructured mesh finite element model is used here. An absorption-like term is introduced to the Navier–Stokes equations in order to control the conditioning of the matrix equation in the numerical solution process and thus improve the stability. A wetting and drying algorithm is used here to allow the free surface height to be treated with a high level of implicitness and stability. The 3D model has been validated by comparing the results with the published experimental data. Good agreement has been achieved at six selected locations. This study shows that the 3D unstructured mesh model is capable of capturing the 3D hydraulic aspects and complicated local flows around structures in simulation of dam-break flows. 相似文献
397.
Liqun?Lyu Zhaoyin?WangEmail authorView authors OrcID profile P.?Cui 《Environmental Fluid Mechanics》2017,17(1):139-158
A typical two-phase debris flow exhibits a high and steep flow head consisting of rolling boulders and cobbles with intermittent or fluctuating velocity. The relative motion between the solid phase and the liquid phase is obvious. The motion of a two-phase debris flow depends not only on the rheological properties of the flow, but also on the energy transmission between the solid and liquid phases. Several models have been developed to study two-phase debris flows. An essential shortcoming of most of these models is the omission of the interaction between the two phases and identification of the different roles of the different materials in two-phase debris flows. The tracer particles were used for the velocity of solid phase and the velocity of liquid phase was calculated by the water velocity on the surface of the debris flow in the experiments. This paper analyzed the intermittent feature of two-phase debris flows based on videos of debris flows in the field and flume experiments. The experiments showed that the height of the head of the two-phase debris flow increased gradually in the initiation stage and reached equilibrium at a certain distance from the start of the debris flow. The height growth and the velocity of the flow head showed fluctuating characteristics. Model equations were established and the analyses proved that the average velocity of the two-phase debris flow head was proportional to the flood discharge and inversely proportional to the volume of the debris flow head. 相似文献
398.
Jasim?ImranEmail authorView authors OrcID profile Sadia?M.?Khan Carlos?Pirmez Gary?Parker 《Environmental Fluid Mechanics》2017,17(1):159-186
The scaling problem associated with the modeling of turbidity currents has been recognized but is yet to be explored systematically. This paper presents an analysis of the dimensionless governing equations of turbidity currents to investigate the scale effect. Three types of flow conditions are considered: (i) conservative density current; (ii) purely depositional turbidity current; and (iii) mixed erosional/depositional turbidity current. Two controlling dimensionless numbers, the Froude number and the Reynolds number, appear in the non-dimensional governing equations. When densimetric Froude similarity is satisfied, the analysis shows that the results would be scale-invariant for conservative density current under the rough turbulent condition. In the case of purely depositional flows, truly scale-invariant results cannot be obtained, as the Reynolds-mediated scale effects appear in the bottom boundary conditions of the flow velocity and sediment fall velocity. However, the scale effect would be relatively modest. The Reynolds effect becomes more significant for erosional or mixed erosional/depositional turbidity currents as Reynolds-mediated scale effects also appear in the sediment entrainment relation. Numerical simulations have been conducted at three different scales by considering densimetric Froude scaling alone as well as combined densimetric Froude and Reynolds similarity. Simulation results confirm that although the scaling of densimetric Froude number alone can produce scale-invariable results for conservative density currents, variations occur in the case of turbidity currents. The results become scale invariant when densimetric Froude and Reynolds similarities are satisfied simultaneously. 相似文献
399.
Gunnar Cerwén Carola Wingren Mattias Qviström 《Journal of Environmental Planning and Management》2017,60(7):1253-1275
While soundscape is increasingly acknowledged within landscape planning and design discourse, there is little research that clarifies how soundscapes are actually dealt with in landscape architecture practice – partly owing to methodological insufficiencies. This paper, therefore, describes a model for evaluating soundscape treatment in landscape design proposals, focusing on three key aspects. With the dual aim of testing the model, and learning more about how soundscape is approached in practice, the paper spotlights a major design competition for a new cemetery in Sweden. The model proved fruitful and easy to apply. It showed that only limited attention was paid to soundscape in the competition as a whole, and was a useful means of pinpointing proposals where soundscape was fully considered as a design feature; one competition entry that did so is described in the paper. Discussions cover design practice, trends in the competition and model application. 相似文献
400.
Sarah E. Crawford Thomas Hartung Henner Hollert Björn Mathes Bennard van Ravenzwaay Thomas Steger-Hartmann Christoph Studer Harald F. Krug 《Environmental Sciences Europe》2017,29(1):16
Green Toxicology refers to the application of predictive toxicology in the sustainable development and production of new less harmful materials and chemicals, subsequently reducing waste and exposure. Built upon the foundation of “Green Chemistry” and “Green Engineering”, “Green Toxicology” aims to shape future manufacturing processes and safe synthesis of chemicals in terms of environmental and human health impacts. Being an integral part of Green Chemistry, the principles of Green Toxicology amplify the role of health-related aspects for the benefit of consumers and the environment, in addition to being economical for manufacturing companies. Due to the costly development and preparation of new materials and chemicals for market entry, it is no longer practical to ignore the safety and environmental status of new products during product development stages. However, this is only possible if toxicologists and chemists work together early on in the development of materials and chemicals to utilize safe design strategies and innovative in vitro and in silico tools. This paper discusses some of the most relevant aspects, advances and limitations of the emergence of Green Toxicology from the perspective of different industry and research groups. The integration of new testing methods and strategies in product development, testing and regulation stages are presented with examples of the application of in silico, omics and in vitro methods. Other tools for Green Toxicology, including the reduction of animal testing, alternative test methods, and read-across approaches are also discussed. 相似文献