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471.
472.
A comparison of simulated and observed ozone mixing ratios for the summer of 1998 in Western Europe 总被引:1,自引:0,他引:1
H. Schmidt C. Derognat R. Vautard M. Beekmann 《Atmospheric environment (Oxford, England : 1994)》2001,35(36):6277-6297
This study describes and evaluates the newly developed European scale Eulerian chemistry transport model CHIMERE-continental. The model is designed for seasonal simulations and real time forecasts without the use of super-computers. For the purpose of model evaluation simulated ozone mixing ratios for the period between 1 May 1998 and 30 September 1998 are compared to observational data from 115 European surface sites. In order to facilitate the interpretation of future forecasts a statistic is established to estimate the reliability of a simulated pollution level. Besides this, the comparison is done by means of time series, scatter plots, a spectral analysis and the calculation of RMS-errors and biases of the model results corresponding to each observation site. It turns out that the mean RMS-error of the simulated daily maximum ozone mixing ratio for the sites considered a priori as well suited for a model comparison is about 10 ppb. For the same period but a reduced number of sites observed concentrations of NO2 and ethene are compared to simulated values. Difficulties encountered with the representativeness of observations when trying to evaluate a mesoscale air pollution model are discussed. 相似文献
473.
Winfried Schröder Hubert Bast Roland Pesch Gunther Schmidt Ellen Kiel 《Environmental Sciences Europe》2007,19(2):115-122
Goal and Scope
The coastal zones of Lower Saxony (Germany) are former malaria regions. Malaria had finally become extinct in the early 1950s, and subsequently related scientific investigations declined. But from that time until nowadays, the vector in the form of Anopheles mosquitoes has still been present in Lower Saxony. Thus, the question arises, whether a new autochthon transmission could take place due to the monthly mean temperatures of the recent years. Answering this question was one goal of the investigation at hand. Another one was to examine the spatial and temporal structure of potential transmissions in respect to the predicted increase of the air temperatures according to the IPCC scenarios.Methods
Current information about anophelines and their characteristics within Germany, such as details on historical incidences, breeding preferences, longevity or distribution of the respective species, were collected by literature research. Further, measurement and incidence data had to be collected and processed: temperature values were provided by the Deutscher Wetterdienst (DWD), and recent findings of Anopheles were supplied by the former Niedersächsisches Landesamt für Ökologie (NLÖ) as a data bank. Then temperature maps were calculated for the three periods (1947–1960, 1961–1990, 1985–2004) by means of Kriging. To model areas at risk, the transmission potential for a new vivax malaria spread in respect to temperature was computed using the Basic Reproduction Rate (R0) formula. It provides the average number of secondary infections produced when a single infected individual is introduced into a potential host population in which each member is susceptible.Results
The computations corroborate a climate warming between the 30-years interval from 1961 to 1990 and the period from 1985 to 2004. According to the rise of the air temperature as predicted by the IPCC scenarios, the spatial pattern of potential malaria outbreak was calculated for 2020, 2060 an 2100. To this end, for each of these years a best-case-scenario with the lowest reasonable temperature increases (+0.3°C, +0.9°C, +1.4°C) and a worst-case-scenario implying the highest plausible temperature rise (+0.9°C, +3.3°C, +5.8°C) were assumed. While in 2020 the maximum duration of the transmission risk is estimated to last four months, in 2100 the vivax transmission will be likely from May until October.Discussion
Correlated with the higher monthly mean temperature values, the risk of a vivax transmission is increasing as temperature is the determining variable of the mathematical model. Therefore Lower Saxony is at risk of a new outbreak of vivax malaria assuming no other risk factors are of relevance.Conclusions
The study could demonstrate that most parts of the country lie within a transmission zone with a duration of two months. The areas containing the highest risk with a transmission length of three months are located around Nordhorn and Hameln, and within the rectangle of Celle, Hannover, Helmstedt and Wolfsburg. These areas match with recent Anopheles larvae finding by the NLÖ, thus, only the pathogen is lacking for a successful transmission. And as Germany is not an endemic malaria zone, the pathogen can enter the country most likely by infected people or imported mosquitoes that transport it in their guts.Recommendations and Perspectives
The results should be understood as a request for more comprehensive investigations in that field. This would be an essential basis for a successful risk monitoring and precautionary management. Although the chances of a new endemic malaria disease in Germany seem to be considerably low today, it would be better to be prepared than to be suddenly faced with the unexpected. 相似文献474.
Life cycle assessment part 1: framework, goal and scope definition, inventory analysis, and applications 总被引:30,自引:0,他引:30
Rebitzer G Ekvall T Frischknecht R Hunkeler D Norris G Rydberg T Schmidt WP Suh S Weidema BP Pennington DW 《Environment international》2004,30(5):701-720
Sustainable development requires methods and tools to measure and compare the environmental impacts of human activities for the provision of goods and services (both of which are summarized under the term "products"). Environmental impacts include those from emissions into the environment and through the consumption of resources, as well as other interventions (e.g., land use) associated with providing products that occur when extracting resources, producing materials, manufacturing the products, during consumption/use, and at the products' end-of-life (collection/sorting, reuse, recycling, waste disposal). These emissions and consumptions contribute to a wide range of impacts, such as climate change, stratospheric ozone depletion, tropospheric ozone (smog) creation, eutrophication, acidification, toxicological stress on human health and ecosystems, the depletion of resources, water use, land use, and noise-among others. A clear need, therefore, exists to be proactive and to provide complimentary insights, apart from current regulatory practices, to help reduce such impacts. Practitioners and researchers from many domains come together in life cycle assessment (LCA) to calculate indicators of the aforementioned potential environmental impacts that are linked to products-supporting the identification of opportunities for pollution prevention and reductions in resource consumption while taking the entire product life cycle into consideration. This paper, part 1 in a series of two, introduces the LCA framework and procedure, outlines how to define and model a product's life cycle, and provides an overview of available methods and tools for tabulating and compiling associated emissions and resource consumption data in a life cycle inventory (LCI). It also discusses the application of LCA in industry and policy making. The second paper, by Pennington et al. (Environ. Int. 2003, in press), highlights the key features, summarises available approaches, and outlines the key challenges of assessing the aforementioned inventory data in terms of contributions to environmental impacts (life cycle impact assessment, LCIA). 相似文献
475.
Scott T. Larned David B. Arscott Jochen Schmidt Jan C. Diettrich 《Journal of the American Water Resources Association》2010,46(3):541-553
Larned, Scott T., David B. Arscott, Jochen Schmidt, and Jan C. Diettrich, 2010. A Framework for Analyzing Longitudinal and Temporal Variation in River Flow and Developing Flow-Ecology Relationships. Journal of the American Water Resources Association (JAWRA) 46(3):541-553. DOI: 10.1111/j.1752-1688.2010.00433.x Abstract: We propose a framework for analyzing longitudinal flow variation and exploring its ecological consequences in four steps: (1) generating longitudinally continuous flow estimates; (2) computing indices that describe site-specific and longitudinal flow variation, including intermittence; (3) quantifying and visualizing longitudinal dynamics; (4) developing quantitative relationships between hydrological indices and ecological variables (flow-ecology relationships). We give examples of each step, using data from a New Zealand river and an empirical longitudinal flow model, ELFMOD. ELFMOD uses spot-gauging data and flow or proxy variable time series to estimate flow magnitude and state (flowing or dry) at user-defined intervals along river sections. Analyses of flow-ecology relationships for the New Zealand river indicated that fish and benthic and hyporheic invertebrate communities responded strongly to variation in mean annual flow permanence, flow duration, dry duration, drying frequency, inter-flood duration, and distances to flowing reaches. To put longitudinal flow variation into a broader context and guide future research, we propose a conceptual model that combines elements of two contrasting perspectives: rivers as longitudinal continua, and rivers as patch mosaics. In this conceptual model, hydrologically complex rivers are composed of linear sequences of nested hydrological gradients, which are bordered by hydrogeomorphic discontinuities, and which collectively generate hydrological dynamics at river-section scales. 相似文献
476.
Kenneth D. Schmidt 《Journal of the American Water Resources Association》1973,9(3):598-606
ABSTRACT The Cortaro Area is currently the depository for much of the liquid waste from the City of Tucson. In the past, more than one-half of the sewage effluent was used for crop irrigation. However, since 1970 virtually all of the sewage effluent has been percolated in the normally dry Santa Cruz River channel. Nitrate and chloride contents were monitored monthly in water samples from about 20 large-capacity irrigation wells. Contents and seasonal trends for these constituents were closely related to the disposal of sewage effluent. Water quality problems other than nitrate include total dissolved solids, boron, coliform, and lead. High lead contents in the area appear to be a natural phenomenon and the coliform contents are likely related to poor well construction. The other quality problems are primarily due to sewage effluent. 相似文献
477.
478.
W. J. Schmidt 《Die Naturwissenschaften》1924,12(16):296-303
479.
480.
W. J. Schmidt 《Die Naturwissenschaften》1952,39(14):313-318