全文获取类型
收费全文 | 578篇 |
免费 | 42篇 |
国内免费 | 104篇 |
专业分类
安全科学 | 362篇 |
废物处理 | 14篇 |
环保管理 | 12篇 |
综合类 | 172篇 |
基础理论 | 27篇 |
污染及防治 | 105篇 |
评价与监测 | 12篇 |
社会与环境 | 6篇 |
灾害及防治 | 14篇 |
出版年
2024年 | 3篇 |
2023年 | 41篇 |
2022年 | 42篇 |
2021年 | 28篇 |
2020年 | 29篇 |
2019年 | 39篇 |
2018年 | 32篇 |
2017年 | 23篇 |
2016年 | 25篇 |
2015年 | 20篇 |
2014年 | 36篇 |
2013年 | 29篇 |
2012年 | 54篇 |
2011年 | 39篇 |
2010年 | 42篇 |
2009年 | 34篇 |
2008年 | 25篇 |
2007年 | 34篇 |
2006年 | 37篇 |
2005年 | 17篇 |
2004年 | 9篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 18篇 |
2000年 | 2篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
排序方式: 共有724条查询结果,搜索用时 15 毫秒
231.
《Atmospheric environment(England)》1984,18(10):2159-2165
By means of gas chromatography with nitrogen sensitive detection and negative ion chemical ionization mass spectrometric detection 7 mononitro-PAH, 9-nitroanthracene, x-nitro-4,5-methylene-phenanthrene, 3-nitrofluoranthene, 1- and 2-nitropyrene, 10-nitrobenz(a)anthracene and 6-nitrobenzo-(a)pyrene have been identied in samples of airborne particulate matter. Furthermore, 8-nitrofluoranthene has been tentatively identified. The amounts of mononitro-PAH are one to two orders of magnitude lower than the most common carcinogenic PAH, as e.g. benzo(a)pyrene. Filter effects have been studied, 9-nitroanthracene can be transformed during sampling at low atmospheric concentrations of NO2 and photochemical oxidants to 9,10-dinitroanthracene and 10-nitroanthrone. 相似文献
232.
Qianqian Hong Cheng Liu Qihou Hu Chengzhi Xing Wei Tan Ting Liu Jianguo Liu 《环境科学学报(英文版)》2021,33(5):119-134
Information on the vertical distribution of air pollutants is essential for understanding their spatiotemporal evolution underlying urban atmospheric environment. This paper presents the SO2 profiles based on ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements from March 2018 to February 2019 in Hefei, East China. SO2 decrease rapidly with increasing heights in the warm season, while lifted layers were observed in the cold season, indicating accumulation or long-range transport of SO2 in different seasons might occur at different heights. The diurnal variations of SO2 were roughly consistent for all four seasons, exhibiting the minimum at noon and higher values in the morning and late afternoon. Lifted layers of SO2 were observed in the morning for fall and winter, implying the accumulation or transport of SO2 in the morning mainly occurred at the top of the boundary layer. The bivariate polar plots showed that weighted SO2 concentrations in the lower altitude were weakly dependent on wind, but in the middle and upper altitudes, higher weighted SO2 concentrations were observed under conditions of middle-high wind speed. Concentration weighted trajectory (CWT) analysis suggested that potential sources of SO2 in spring and summer were local and transported mainly occurred in the lower altitude from southern and eastern areas; while in fall and winter, SO2 concentrations were deeply affected by long-range transport from northwestern and northern polluted regions in the middle and upper altitudes. Our findings provide new insight into the impacts of regional transport at different heights in the boundary layer on SO2 pollution. 相似文献
233.
粮食安全事关国计民生,近年来粮仓火灾多发,对于粮食火灾安全的基础性研究,显得愈加迫切。基于自主设计的贯穿气流条件下的散粒堆垛引燃与蔓延燃烧特性研究实验平台,针对两种含水率水稻,在不同贯穿气流条件下,开展了引燃与内部蔓延燃烧特性研究。结果表明,水稻含水率对其燃烧特性具有重要影响,即,对于13%含水率水稻,采用高温电热细棒插入堆垛内进行引燃45 min,并未引燃;然而,对于3%含水率水稻,仅引燃4 min,堆垛即形成迅速剧烈蔓延燃烧,中心区域燃烧温度高达1 200℃,最大蔓延速度约0.8 cm/s,引燃前的最大升温速率约200℃/min。此外,结果还表明,贯穿气流条件下,远离中心区域的四周水稻升温较慢且剩余一些最终未引燃,水稻堆垛内部主要呈向下且不断扩大的蔓延燃烧特征。最后,13%含水率水稻被灼热引火源作用结束后形成的碳化圈大小表明,机械通风气调作用对于灼热源的引燃作用具有一定的抑制作用。 相似文献
234.
针对火源位置输入偏差导致的FARSITE林火行为模型火线预测不准确的问题,提出了一种基于集合卡曼滤波算法的动态修正方法。利用FARSITE对复杂工况下的林火蔓延过程进行数值模拟,以火线位置为待修正参量,以均方根误差(RMSE)为评价指标,对算法的可行性进行了验证,并研究了算法的集合元素个数,观测数据标准差及同化频率对FARSITE预测偏差的修正效果的影响。结果表明:算法能显著提高FARSITE火线预测精度;逐时同化时:集合元素个数为5时,算法的修正效果并不理想,随着集合元素个数增大,样本误差减小,修正效果得到改善,但增大到30以上时,修正能力的提升就不再明显;观测数据标准差大小与RMSE值呈正相关;给定条件下当同化频率由1 h/次降低至2 h/次,整个模拟时长内的误差仍能得到较好控制,RMSE曲线并不会过快增长。 相似文献
235.
巢湖流域水污染防治研究 总被引:5,自引:0,他引:5
从区域的角度分析了巢湖流域的全局及局部水环境的现状和污染原因,并从生态防治和技术性防治的角度进行了相关研究,在湖泊水体的内源污染控制和新技术上进行了探讨。 相似文献
236.
ZHU Ren-bin SUN Li-guang ZHAO San-ping XIE Zhou-qing LIU Xiao-dong YIN Xue-bin 《环境科学学报(英文版)》2005,17(5):789-793
IntroductionMethane ( CH4) is a radiatively active trace gas ,contributing approximately 20 % to global warming(Bouwman, 1990) . An increasing concentration in theatmosphere, and ill-defined sink and source strengths haveled to a proliferation of the stud… 相似文献
237.
Since the ban on the use of organochlorine pesticides (OCPs) such as dichloro-diphenyl-trichloroethane (DDT) and hexachlorocyclohexane(HCH) in agriculture, their levels have generally dropped. In a number of cases, however, the levels of these OCPs were found to be unchanging or even increasing after the ban. With the aim to unveil the possible causes of these exceptions, we collected two lake cores from King George Island, West Antarctica, and determined their accumulation flux profiles and temporal trends of these OCPs. In the lake core sediments with glacier meltwater input, the accumulation flux of DDT shows an abnormal peak around 1980s in addition to the expected one in 1960s. In the lake core sediments without glacier meltwater input, the accumulation flux of DDT shows a gradual decline trend after the peak in 1960s. This striking difference in the DDT flux profiles between the two lake cores is most likely caused by the regional climate warming and the resulted discharge of the DDT stored in the Antarctic ice cap into the lakes in the Antarctic glacier frontier. Furthermore, to investigate the change of OCPs loadings in the Antarctic coastal ecosystem, we reconstructed the HCH and DDT concentration profiles in penguin droppings and observed a gradual increase for the former and a continuous decrease for the latter during the past 50 years. The increase of HCH seems to be due to the regional warming from the early 1970s and the resulted HCH discharge to the coastal ecosystem by glaciers' meltwater and the illegal use of HCH in the Southern Hemisphere in the recent decade. The different temporal trends of HCH and DDT accumulation rate in the lake core with glacier meltwater input and the aged penguin droppings can be explained by their different water-soluble property. 相似文献
238.
WANG Zhi-gang LIU Wen-qing ZHAO Nan-jing LI Hong-bin ZHANG Yu-jun SI-MA Wei-cang LIU Jian-guo . School of Earth Space Science University of Science Technology of China Hefei China. . Key Laboratory of Environmental Optics Technology Anhui Institute of Optics Fine Mechanics Chinese Academy of Sciences Hefei China 《环境科学学报(英文版)》2007,(7)
Taihu Lake is one of the five biggest lakes in China. Surface water samples from 26 sampling sites of Taihu Lake were collected. Furthermore wet chemical analysis (CODCr and BOD5) and measurement of three dimensional excitation-emission matrix (3DEEM) spectra in the laboratory have been conducted. Using parallel factor analysis (PARAFAC) model, three components of colored dissolved organic matter (CDOM) have been identified successfully, based on the analysis of 3DEEM data. The characteristics of the three components also have been described by comparing them to some components of CDOM, identified in earlier researches. Meanwhile, spatial variations of concentration for the three components in Taihu Lake have been analyzed, and the result indicates that the concentration of component 1 depends more on the situation of wastewater pollution and can be used as the indicator of wastewater pollution. The relationship between the concentrations of the three components and results of the wet chemical analysis show that none of the three components can be used as indicators of gross organic matter in water. However, the concentrations of all the three components have obvious linear relationships with the BOD5 value, especially for component 1 (r=0.72878). Finally, the potential applications of the composition analysis based on 3DEEM and PARAFAC model in water quality monitoring have been illuminated. 相似文献
239.
《Atmospheric environment (Oxford, England : 1994)》1999,33(27):4413-4419
Conductometry was used to study the kinetics of the oxidation of hydrogen sulfite, HSO−3, by hydrogen peroxide in aqueous non-buffered solution at the low concentration level of 10−5–10−6 M, typically found in cloud water. The kinetic data confirm that the rate law reported for the pH range 3–6 at higher concentration levels, rate=kH·[H+]·[HSO−3]·[H2O2], is valid at the low concentration level and at low ionic strength Ic. At 298 K and Ic=1.5×10−4 M, third-order rate constant kH was found to be kH=(9.1±0.5)×107 M−2 s−1. The temperature dependence of kH led to an activation energy of Ea=29.7±0.9 kJ mol−1. The effect of the ionic strength (adjusted with NaCl) on rate constant kH was studied in the range Ic=2×10−4–5.0 M at pH=4.5–5.2 by conductometry and stopped-flow spectrophotometry. The dependence of kH on Ic can be described with a semi-empirical relationship, which is useful for the purpose of comparison and extrapolation. The kinetic data obtained are critically compared with those reported earlier. 相似文献
240.