全文获取类型
收费全文 | 720篇 |
免费 | 46篇 |
国内免费 | 127篇 |
专业分类
安全科学 | 50篇 |
废物处理 | 3篇 |
环保管理 | 83篇 |
综合类 | 363篇 |
基础理论 | 53篇 |
污染及防治 | 120篇 |
评价与监测 | 127篇 |
社会与环境 | 34篇 |
灾害及防治 | 60篇 |
出版年
2024年 | 2篇 |
2023年 | 30篇 |
2022年 | 27篇 |
2021年 | 26篇 |
2020年 | 37篇 |
2019年 | 25篇 |
2018年 | 32篇 |
2017年 | 23篇 |
2016年 | 20篇 |
2015年 | 20篇 |
2014年 | 36篇 |
2013年 | 30篇 |
2012年 | 44篇 |
2011年 | 67篇 |
2010年 | 43篇 |
2009年 | 51篇 |
2008年 | 41篇 |
2007年 | 46篇 |
2006年 | 21篇 |
2005年 | 21篇 |
2004年 | 22篇 |
2003年 | 20篇 |
2002年 | 19篇 |
2001年 | 20篇 |
2000年 | 19篇 |
1999年 | 21篇 |
1998年 | 23篇 |
1997年 | 20篇 |
1996年 | 7篇 |
1995年 | 21篇 |
1994年 | 15篇 |
1993年 | 6篇 |
1992年 | 13篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有893条查询结果,搜索用时 31 毫秒
81.
建立了人、机、大气环境扰动的动力学模型。形成一个便于仿真计算的人-机-环境系统模型,针对驾驶员完成俯仰跟踪任务,研究了大气扰动对驾驶员控制特性和人-机闭环特性的影响。 相似文献
82.
83.
Zhuikova T. V. Bezel' V. S. Pozolotina V. N. Severyukhina O. A. 《Russian Journal of Ecology》2002,33(6):407-412
The reproductive capacity of Taraxacum officinale s.l. (two morphological forms: T. off. f. dahlstedtii Lindb. fil. and T. off. f. pectinatiforme Lindb. fil.) under conditions of chemical environmental pollution was studied in years differing in weather conditions. The number of generative shoots in plants increased along the toxic load gradient, which led to an increase in the total number of seeds and the weight of filled seeds. The relative energy value of seeds was determined from the amount of plastic substances in them. The number of seeds was shown to increase at a considerably higher rate than the energy expenditures for the formation of each seed. A general principle was revealed that determines the energy expenditures for the formation of a normal seed in both T. officinale forms under different weather conditions and under the chemical pollution of the environment. 相似文献
84.
Secondary containment (bunds, drip trays, interceptors/sumps) is an integral part of many chemical, petrochemical, as well as agricultural, food and pharmaceutical facilities. Bunds are the built-in cases for accidental liquid substance spillage where there is a hazard that a substance could leak into the surroundings and the potential of health or environmental damage. The authors focus on the cases installed in large-volume atmospheric tanks storing hazardous chemicals in liquid form, where the bund failure occurred. In the first part of the study, a database of these accidents was created, numbering a total of 15 items. Attention was paid to the course of the accident, its causes and consequences. Several basic representative scenarios of bund failure have also been developed. The second part of the study is devoted mainly to the measures against the bund failure, such as risk assessment, technical and organizational measures. The aim of this study is to provide readers (including experts in the field of safety engineering, maintenance experts and building designers) with the information that can subsequently be used in the risk assessment of bund failure, possibly also for planning the construction of new bunds, or revitalization and maintenance of the existing ones. 相似文献
85.
本文介绍采用航空遥感技术和实地调查研究相结合的方法,分析了沈阳市烟囱数量、高度、密度以及高、中、低架烟囱的分布状况和特点,同时与大气污染监测结果对照分析了沈阳市煤烟型大气污染的规律及特点,研究了沈阳市烟囱分布对大气污染的影响。最后,提出了沈阳市燃煤污染的防治途径。 相似文献
86.
Dragana??or?evi?Email author Drubavka?Radmanovi? Aleksandra?Mihajlidi-Zeli? Mila?Ili? Petar?Pfendt Zorka?Vukmirovi? Pedrag?Poli? 《Environmental Chemistry Letters》2004,2(3):147-150
We applied statistical methods to the data of a 5-year sampling period to characterize the features of trace elements in airborne particulate matter at the South Adriatic Coast. The analysis of surface soil samples was also performed. The data were processed by cluster analysis, enrichment factor determination and receptor rose statistics. It is shown that the principal element association consists of Fe, Mn and Ti originating from surface material resuspension. Hg and Se were shown to originate from more complex natural and anthropogenic processes. A strong emission source of Cd and Se was identified in the SSE direction.Selected article from the Regional Symposium on Chemistry and Environment Krusevac, Serbia, June 2003, organized by Dr. Branimir Jovancicevic. 相似文献
87.
Tov Elperin Nathan Kleeorin Michael A. Liberman Victor S. L’vov Igor Rogachevskii 《Environmental Fluid Mechanics》2007,7(2):173-193
A mechanism of formation of small-scale inhomogeneities in spatial distributions of aerosols and droplets associated with
clustering instability in the atmospheric turbulent flow is discussed. The particle clustering is a consequence of a spontaneous
breakdown of their homogeneous space distribution due to the clustering instability, and is caused by a combined effect of
the particle inertia and a finite correlation time of the turbulent velocity field. In this paper a theoretical approach proposed
in Elperin et al. (2002) Phys Rev E 66:036302 is further developed and applied to investigate the mechanisms of formation
of small-scale aerosol inhomogeneities in the atmospheric turbulent flow. The theory of the particle clustering instability
is extended to the case when the particle Stokes time is larger than the Kolmogorov time scale, but is much smaller than the
correlation time at the integral scale of turbulence. We determined the criterion of the clustering instability for the Stokes
number larger than 1. We discussed applications of the analyzed effects to the dynamics of aerosols and droplets in the atmospheric
turbulent flow. 相似文献
88.
本文介绍了成都市大气降尘放射性水平的监测结果。发现降尘中除有少量天然核素外,还尚存有以往大气层核试验释放的裂变核素90Sr和137Cs。平均年沉降量90Sr为102Bq·m-2·Y-1,137Cs为131Bq·m-2·Y-1。由大气90Sr和137Cs沉降所致公众辐射剂量为168μSr·a-1,是限值的2‰。所以,降尘中放射性造成的辐射影响是很小的。 相似文献
89.
天津地区污染天气分析中垂直扩散指标构建及运用 总被引:2,自引:2,他引:0
基于255 m气象塔风、温和PM_(2.5)质量浓度数据获取天津地区大气稳定度特征,利用中尺度大气化学模式构建垂直扩散指数β和φ,开展天津地区污染天气预报中垂直扩散分析方法的研究,以期提高天津地区重污染天气预报预警准确率.结果表明,综合运用大气稳定度、基于边界层平均PM_(2.5)质量浓度与近地面PM_(2.5)质量浓度比值构建的垂直扩散指数β,基于数值模式chemdiag功能(以CO为示踪物)构建的垂直扩散指数φ,可以在污染天气预报中较好的进行大气污染物垂直扩散能力分析.当07:00~08:00和18:00~20:00大气稳定度为D及以上时,相比大气稳定为C及以下时,出现重污染天气的概率成10倍的增加;使用垂直扩散指数β和风速双重指标判断重污染天气,比单一的风速指标判断准确率提升67%;垂直扩散指数φ与近地面PM_(2.5)质量浓度相关系数达到0.8,当垂直扩散指数φ小于0.52时,重污染天气概率75%,可识别59%的重污染天气. 相似文献
90.
WRF模式对污染天气下边界层高度的模拟研究 总被引:1,自引:0,他引:1
大气边界层高度是影响大气污染物浓度的重要因素之一,但数值模式中选择不同边界层参数化方案模拟的边界层高度有很大差异.利用WRF模式中5种边界层参数化方案及2006~2007年春、秋、冬3季河北香河地区激光雷达观测资料,对比分析了污染天气下,不同边界层方案对边界层高度的模拟效果,并分析了误差产生的可能原因.结果表明:5种参数化方案均能模拟出3季污染天气下边界层高度的变化特征,但各方案模拟的边界层高度与观测之间均存在较大误差.模拟的最大边界层高度月变化特征显示,秋冬季的模拟结果与观测值匹配较好,春季偏差较大;模拟的边界层高度日变化显示,均方根误差:春季 > 秋季 > 冬季,且误差在午后(14:00~18:00)更加明显;对该地区而言,非局地YSU方案能较好地模拟污染天气下的边界层高度;各参数化方案中边界层高度计算方法的不同及对大气廓线、湍流动能的模拟差异,可能是造成模拟边界层高度产生误差的主要原因. 相似文献