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321.
Summary. Surrogate leaves treated with methanolic leaf surface extracts of Brassica napus L. (cv Express) plants that received three different sulphur fertilisation treatments showed even more marked differences by the oviposition choice of Delia radicum L. than the potted plants. This confirms that the oviposition preference of D. radicum is mediated by chemical compounds on the leaf surface and that the quality of host-plants in terms of their nutrition status can be perceived by the female insect.The oviposition data were positively correlated with the content of fractionated surface extracts containing either CIF (cabbage identification factor; 1,2-dehydro-3-thia- 4,10,10b-triaza-cyclopenta[.a.]fluorine-1-carboxylic acid) or glucosinolates. Electrophysiological recordings from the tarsal chemoreceptor sensilla C5 and D3,4 showed that receptor neurons react to glucosinolate- and CIF-fractions. We found that the chemosensory activity of specific glucosinolate- and CIF-receptor neurons corresponded with the respective behavioural activity in the oviposition choice assays. The responses of D. radicum to glucosinolates in the electrophysiological recordings studies corresponded to the observed oviposition preference on plants or artificial leaves characterised with an higher amount of glucosinolates on leave surfaces. The presented data suggested that CIF and glucosinolates are involved in host-plant preference of D. radicum and are perceived by tarsal chemoreceptors.  相似文献   
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The engagement of environmental non-governmental groups in collaborative communication efforts and decision-making about climate change remains a significant challenge. In Latin America, the website Intercambio Climático was set up to attempt to play a breakthrough role in the region's discussion of climate change. This case study focuses on the development, accomplishments, and challenges of this unique online communication initiative among non-governmental organizations working in climate change issues in Latin America with a US-based partner, as a vehicle to achieve their goals. We used secondary data and in-depth interviews to examine this platform's role in disseminating information and influencing decision-making. The results suggest that generally the participants perceive the website positively, but there are also problematic aspects of the collaboration that are not fully recognized by the members, which prevents a more functional and effective communication strategy.  相似文献   
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Environmental Science and Pollution Research - The growing use of pharmaceutical drugs has become a major environmental issue considering that these substances (or their metabolites) end up...  相似文献   
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We propose truncated and power‐transformed (TPT) models for daily rainfall and we derive the generalized extreme value (GEV) limit distributions for these models. We find that these limit distributions belong to the domain of attraction of the Fréchet family when the parent distribution of the daily values is a TPT t‐Student model. In this case, the shape parameter of the limiting GEV model depends on the degrees of freedom and the power transformation parameter. When the parent distribution of the daily values is a TPT Normal model, the limiting GEV model is independent of the parameters of the parent model. We perform a detailed inference and predictive analysis to verify these theoretical results using a Bayesian approach. Markov Chain Monte Carlo methods (MCMC) were used to estimate the posterior distribution of the parameters of the t‐Student model for daily rainfall on one hand, and to estimate the posterior distribution of the parameters of the GEV model for the annual maxima on the other hand. Numerical results are presented for two locations: Maiquetía (Vargas State), and La Mariposa (Miranda State), Venezuela. Simulations from the predictive distribution of the daily values suggest a good approximation between the extreme distribution of the TPT t‐Student model and the Fréchet model found by standard extreme value limit theory. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
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We compare ground rainfall with purely deterministic Regional Climate Model (RCM) simulations within a Bayesian framework. A truncated normal model is fitted to the observed ground data to represent spatial variability. The predictive posterior distribution of the spatially aggregated rainfall is obtained by using a Markov chain Monte Carlo method and compared to the RCM simulations. Also, the predictive posterior distribution of the RCM output is downscaled using the truncated normal model and obtaining pointwise rainfall estimates from aerial observations which are compared to the ground observations. These two procedures allow us to determine if the differences between the two sources of information are compatible with the variability predicted by the spatial model. Also, point rainfall estimates at locations without rainfall measurements conditioned on RCM observations can be obtained. We considered a set of data from an area in Nebraska for which time is considered fixed and rainfall is accumulated monthly. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
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This article proposes the use of classification trees (CART) as a suitable technique for forecasting the daily exceedance of ozone standards established by Italian law. A model is formulated for predicting, 1 and 2 days beforehand, the most probable class of the maximum daily urban ozone concentration in the city of Bologna. The standard employed is the so‐called ‘warning level’ (180 μg/m3). Meteorological forecasted variables are considered as predictors. Pollution data show a considerable discrepancy between the dimensions of the two classes of events. The first class includes those days when the observed maximum value exceeds the established standard, while the second class contains those when the observed maximum value does not exceed the said standard. Due to this peculiarity, model selection procedures using cross‐validation usually lead to overpruning. We can overcome this drawback by means of techniques which replicate observations, through the modification of their inclusion probabilities in the cross‐validation sets. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   
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Interest in air quality indices has been increasing in recent years. This is strictly connected with the development and the easy availability of web‐communication and on‐line information. By means of web pages it is indeed possible to give quick and easy‐to‐consult information about air quality in a specific area. We propose a class of air quality indices which are simple to read and easy to understand by citizens and policy‐makers. They are constructed in order to be able to compare situations that differ in time and space. In particular, interest is focused on situations where many monitoring stations are operating in the same area. In this case, which occurs frequently, air pollution data are collected according to three dimensions: time, space and type of pollutant. In order to obtain a synthetic value, the dimensions are reduced by means of aggregation processes that occur by successively applying some aggregating function. The final index may be influenced by the order of aggregation. The hierarchical aggregation here proposed is based on the successive selection of order statistics, i.e. on percentiles and on maxima. The variety of pollutants measured in each area imposes a standardization due to their different effects on the human health. This evaluation comes from epidemiological studies and influences the final value of the index. We propose to use simultaneously more than one index of the selected class and to associate a measure of variability with every index. Such measures of dispersion account for very important additional information. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
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