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91.
郑州市 PM2.5和 PM10质量浓度变化特征分析 总被引:3,自引:0,他引:3
根据郑州市2013年PM2.5和PM10颗粒物连续自动监测数据,对郑州市各国控站点的PM2.5和PM10的达标情况、变化趋势等进行探讨分析。结果表明:2013年郑州市PM10和PM2.5的年均质量浓度均超过了新标准规定的年均值二级标准限值。 PM10和PM2.5月均值峰值出现在1月和10月,谷值出现在8月,各月PM2.5的超标天数都大于PM10。PM10和PM2.5冬季的日均值浓度明显高于其他季节,呈双峰型,夜晚浓度整体高于白天;PM2.5春、夏、秋三季日变化呈单峰型,PM10夏季和秋季呈单峰型,春季呈双峰型。 PM2.5和PM10日均值有着非常显著的线性相关关系,PM2.5和PM10浓度的比值(p)10月最高。 相似文献
92.
Yu Y Wen S Lü H Feng Y Wang X Sheng G Fu J 《Environmental monitoring and assessment》2008,137(1-3):275-285
The diurnal variation of atmospheric carbonyls and VOCs in a forest in south China were studied in summer 2004. Twenty kinds
of carbonyls and eight kinds of VOCs were identified and quantified. Formaldehyde and acetaldehyde were the two most abundant
carbonyls, while the most abundant VOCs were isoprene, followed by o-xylene. Most C3-C10 carbonyls had higher concentrations from 09:00 to 15:00, and their levels were lower during night-time and often reached
the lowest in early morning. Formaldehyde and acetaldehyde, however, showed two high levels in their diurnal patterns partly
due to their different sources and sinks. The VOCs had different diurnal patterns compared to most carbonyls. The highest
concentrations were observed from 03:00 to 06:00 for 1-butene, from 06:00 to 12:00 for isoprene, and from 12:00 to 15:00 for
α-pinene. The highest levels for aromatic hydrocarbons occurred during midnight and the lowest in late afternoon. According
to the study, emissions from vegetation and photo-oxidation of gas-phase hydrocarbons were the main sources for some carbonyls
and VOCs in this region. Other compounds, such as formaldehyde, acetaldehyde and BTEX, showed anthropogenic sources. 相似文献
93.
94.
Li Ning 《中国人口.资源与环境(英文版)》2012,10(2)
China's circular economy is still at the initial stage, whose development has many difficulties and problems requir- ing immediate resolution theoretically and practically. Due to the differences of re... 相似文献
95.
96.
BAYESIAN MODELS OF FORECASTED TIME SERIES1 总被引:1,自引:0,他引:1
Roman Krzysztofowicz 《Journal of the American Water Resources Association》1985,21(5):805-814
Bayesian Processor of Forecasts (BPF) combines a prior distribution, which describes the natural uncertainty about the realization of a hydrologic process, with a likelihood function, which describes the uncertainty in categorical forecasts of that process, and outputs a posterior distribution of the process, conditional upon the forecasts. The posterior distribution provides a means of incorporating uncertain forecasts into optimal decision models. We present fundamentals of building BPF for time series. They include a general formulation, stochastic independence assumptions and their interpretation, computationally tractable models for forecasts of an independent process and a first-order Markov process, and parametric representations for normal-linear processes. An example is shown of an application to the annual time series of seasonal snowmelt runoff volume forecasts. 相似文献
97.
Donald E. Agthe R. Bruce Billings Judith M. Dworkin 《Journal of the American Water Resources Association》1988,24(3):627-630
ABSTRACT: Socioeconomic determinants of individual household water use were estimated using regressions of these characteristics with actual household water use for winter and summer. Results were disaggregated between those consumers who were aware of an increasing block rate price structure and those who were not. Most of the informed group members believed that this price structure did result in significant reductions in water use. Nevertheless, overall water use was greater for the informed group. The determinants of water use were found to differ between informed and uninformed users as well as between winter and summer. The uninformed users were influenced by a larger set of variables in each season than the informed group. In winter, the informed group members with swimming pools and/or arid landscaping used less water than their uninformed counterparts. Summer water use increased with length of tenancy in home for the uninformed group but not for informed, while increasing with ownership for informed consumers. 相似文献
98.
地球系统是宇宙系统的全息缩影,地球上的灾害和天体之间具有全息关系,同样有恒定的周期性。本文根据全息理论对灾害进行分析预测,并建议在灾害研究中应用全息理论. 相似文献
99.
Donald J. Epp C. Edwin Young 《Journal of the American Water Resources Association》1981,17(2):215-224
ABSTRACT: Varying treatment levels to meet seasonal variation in assimilative capacity of streams can reduce total costs of treatment. A mathematical model of a Pennsylvania stream based on a theoretically sound approximation of the physical relationships underlying the distribution of DO in a river system was used to determine discharge constraints for an economic optimization model which produced estimates of sewage treatment cost savings. Increasing the number of flow periods during the year enhances cost reducing opportunities even when land application processes are considered. Also, the least cost treatment process for year around operation may not be the least costly under multiple flow period management. 相似文献
100.
Donald R. Haragan 《Journal of the American Water Resources Association》1976,12(6):1191-1204
ABSTRACT: Space autocorrelation techniques have been used to reveal the nature and spatial distribution of precipitation in the Texas High Plains. Correlation in precipitation amounts varies with both distance and direction, dropping off rapidly with distance, particularly during the warm season. The analyses can be used to estimate storm characteristics in conjunction with a wide variety of problems dealing with irrigation, crop yields, drainage and water supply, and evaluation of artificial weather modification efforts. 相似文献