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151.
A positive surge is a unsteady open channel flow resulting from the rapid rise of the free-surface. The phenomenon may be
observed in water supply canals and channels as well as in some estuaries during spring tidal conditions. The formation and
development of positive surges can be predicted using the method of characteristics and shallow water equations. The paper
is the second part of a study presenting the results from new experimental investigations conducted in a large rectangular
channel. Detailed unsteady velocity measurements were performed with a high temporal resolution using acoustic Doppler velocimetry
and non-intrusive free-surface measurement devices. Several experiments were conducted with the same initial discharge (Q = 0.060 m3/s) and six different gate openings after closure resulting in both non-breaking undular and breaking bores. A comparison
between main features of the undular surges with literature theories demonstrated that the experimental data were mostly in
agreement with Andersen’s theory. The analysis of unsteady flow field including Reynolds stresses confirmed and extended previous
findings about positive surge hydrodynamics. 相似文献
152.
Food Community Networks as Leverage for Social Embeddedness 总被引:1,自引:0,他引:1
Giuseppina Migliore Giorgio Schifani Giovanni Dara Guccione Luigi Cembalo 《Journal of Agricultural and Environmental Ethics》2014,27(4):549-567
Social embeddedness, defined as the interaction of economic activities and social behavior, is used in this study as a conceptual tool to describe the growing phenomenon of food community networks (FCNs). The aim in this paper was to map the system of relations which the FCNs develop both inside and outside the network and, from the number of relations, it was inferred the influence of each FCN upon the formation of new socially embedded economic realities. A particular form of FCN was taken under consideration: solidarity purchase groups (SPGs). Performed with the aid of social network analysis on a sample of SPGs in Sicily (a region in southern Italy), the study allowed us to identify a relational (internal) social embeddedness, in which groups of consumers and farmers are directly influenced by reciprocal interactions, giving rise to more or less numerous links of reciprocity and trust depending on the number of interactions. It was also identified a structural (external) social embeddedness, generated by the nature of relations that the SPGs undertake with the various social actors. From the results of our analysis it emerges that SPGs lie at the intersection of many social realities, influencing them and in turn being influenced by such realities. We highlight the major role played by consumer and environmental associations in affecting the phenomenon of social embeddedness. 相似文献
153.
Nichola Geeson Jane Brandt Giovanni Quaranta Rosanna Salvia 《Environmental management》2014,54(5):1043-1055
Until around 1995 it was challenging to make the scientific results of research projects publicly available except through presentations at meetings or conferences, or as papers in academic journals. Then it began to be clear that the Internet could become the main medium to publish and share new information with a much wider audience. The DESIRE Project (desertification mitigation and remediation of land—a global approach for local solutions) has built on expertise gained in previous projects to develop an innovative online ‘Harmonized Information System’ (HIS). This documents the context, delivery and evaluation of all tasks in the DESIRE Project using non-scientific terminology, with much of it also available in the local languages of the study sites. The DESIRE-HIS makes use of new possibilities for communication, including video clips, interactive tools, and links to social media networks such as Twitter. Dissemination of research results using this approach has required careful planning and design. This paper sets out the steps that have culminated in a complete online Information System about local solutions to global land management problems in desertification-affected areas, including many practical guidelines for responsible land management. As many of those who are affected by desertification do not have Internet access, printable dissemination materials are also available on the DESIRE-HIS. 相似文献
154.
Caserini Stefano Barreto Beatriz Lanfredi Caterina Cappello Giovanni Ross Morrey Dennis Grosso Mario 《Mitigation and Adaptation Strategies for Global Change》2019,24(7):1231-1248
Mitigation and Adaptation Strategies for Global Change - A new process to remove carbon dioxide (CO2) from the atmosphere, by combining commercial industrial technologies with ocean liming and CO2... 相似文献
155.
The present paper reports on an observation that dendrite-like polycrystalline structures from evaporating droplets of wheat grain leakages exhibit bilateral symmetry. The exactness of this symmetry, measured by means of fluctuating asymmetry, varies depending on the cultivar and stress factor influence, and seems to correspond to the seed germination rate. In the bodies of plants, animals, and humans, the exactness of bilateral symmetry is known to reflect the environmental conditions of an organism’s growth, its health, and its success in sexual selection. In polycrystalline structures, formed under the same conditions, the symmetry exactness depends on the properties of the crystallizing solution such as the composition and viscosity; however, it has never been associated with sample quality. We hypothesize here that, as in living nature, the exactness of approximate bilateral symmetry might be considered a quality indicator also in crystallographic methods applied to food quality analysis. 相似文献
156.
Matassoni L Pratesi G Centioli D Cadoni F Lucarelli F Nava S Malesani P 《Journal of environmental monitoring : JEM》2011,13(3):732-742
From February 15th to April 15th 2009, a period characterised by two episodes of Saharan dust outbreaks in Italy, particulate matter (PM) samples were collected at two stations (urban and suburban) in Rome. Some samples were selected and analysed using the SEM-EDS technique to characterise PM, focussing especially on the mineral contribution. Samples were representative both of days affected by Saharan dust episodes and days without this contribution. Cluster analysis allowed the attribution of each of about 67,000 analysed particles to one of the seven main statistical groups based on their composition. Characteristics of the particulate components identified using SEM-EDS analysis were verified by PIXE analysis carried out on filters collected in a suburban area. Ultimately, the contribution of crustal particles was revealed to be consistently high, highlighting the importance of local and regional mineral contributions, as well as those of Saharan origin. Therefore, quantifying all mineral contributions to resuspended particulate could lead to significant reductions of the PM level also on days not influenced by Saharan dust, thus limiting conditions when PM?? daily limit value (DLV) established by European legislation is exceeded. 相似文献
157.
El Bouaidi Widad Libralato Giovanni Douma Mountasser Ounas Abdelaziz Yaacoubi Abdelrani Lofrano Giusy Albarano Luisa Guida Marco Loudiki Mohammed 《Environmental science and pollution research international》2022,29(28):42601-42615
Environmental Science and Pollution Research - In recent years, the proliferation of Harmful Cyanobacterial Blooms (CyanoHABs) has increased with water eutrophication and climate change, impairing... 相似文献
158.
159.
Several extinct sperm whales (stem Physeteroidea) were recently proposed to differ markedly in their feeding ecology from the suction-feeding modern sperm whales Kogia and Physeter. Based on cranial, mandibular, and dental morphology, these Miocene forms were tentatively identified as macroraptorial feeders, able to consume proportionally large prey using their massive teeth and robust jaws. However, until now, no corroborating evidence for the use of teeth during predation was available. We report on a new specimen of the stem physeteroid Acrophyseter, from the late middle to early late Miocene of Peru, displaying unusual bony outgrowths along some of the upper alveoli. Considering their position and outer shape, these are identified as buccal maxillary exostoses. More developed along posterior teeth and in tight contact with the high portion of the dental root outside the bony alveoli, the exostoses are hypothesized to have developed during powerful bites; they may have worked as buttresses, strengthening the teeth when facing intense occlusal forces. These buccal exostoses further support a raptorial feeding technique for Acrophyseter and, indirectly, for other extinct sperm whales with a similar oral apparatus (Brygmophyseter, Livyatan, Zygophyseter). With a wide size range, these Miocene stem physeteroids were major marine macropredators, occupying ecological niches nowadays mostly taken by killer whales. 相似文献
160.
Paris Elaine Cristina Malafatti João Otávio Donizette Sciena Camila Rodrigues Junior Luiz Ferreira Neves Zenatti Alessandra Escote Márcia Tsuyama Moreira Ailton José Freschi Gian Paulo Giovanni 《Environmental science and pollution research international》2021,28(19):23731-23741
Environmental Science and Pollution Research - Nanotechnology has been studied on environmental remediation processes to foster greater photocatalysts efficiency and reuse in wastewater. This study... 相似文献