全文获取类型
收费全文 | 4185篇 |
免费 | 33篇 |
国内免费 | 174篇 |
专业分类
安全科学 | 153篇 |
废物处理 | 150篇 |
环保管理 | 504篇 |
综合类 | 668篇 |
基础理论 | 325篇 |
污染及防治 | 1761篇 |
评价与监测 | 482篇 |
社会与环境 | 265篇 |
灾害及防治 | 84篇 |
出版年
2024年 | 5篇 |
2023年 | 21篇 |
2022年 | 14篇 |
2021年 | 9篇 |
2020年 | 22篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 20篇 |
2016年 | 12篇 |
2015年 | 3篇 |
2014年 | 31篇 |
2013年 | 25篇 |
2012年 | 384篇 |
2011年 | 482篇 |
2010年 | 89篇 |
2009年 | 129篇 |
2008年 | 449篇 |
2007年 | 430篇 |
2006年 | 362篇 |
2005年 | 275篇 |
2004年 | 295篇 |
2003年 | 236篇 |
2002年 | 193篇 |
2001年 | 145篇 |
2000年 | 125篇 |
1999年 | 57篇 |
1998年 | 26篇 |
1997年 | 29篇 |
1996年 | 28篇 |
1995年 | 48篇 |
1994年 | 27篇 |
1993年 | 26篇 |
1992年 | 34篇 |
1991年 | 34篇 |
1990年 | 39篇 |
1989年 | 22篇 |
1988年 | 35篇 |
1987年 | 35篇 |
1986年 | 15篇 |
1985年 | 22篇 |
1984年 | 30篇 |
1983年 | 19篇 |
1982年 | 20篇 |
1981年 | 17篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1974年 | 8篇 |
排序方式: 共有4392条查询结果,搜索用时 9 毫秒
241.
242.
Opel O Palm WU Steffen D Ruck WK 《Environmental pollution (Barking, Essex : 1987)》2011,159(4):924-931
Comparability of sediment analyses for semivolatile organic substances is still low. Neither screening of the sediments nor organic-carbon based normalization is sufficient to obtain comparable results. We are showing the interdependency of grain-size effects with inside-sediment organic-matter distribution for PAH, PCB and organochlorine compounds. Surface sediment samples collected by Van-Veen grab were sieved and analyzed for 16 PAH, 6 PCB and 18 organochlorine pesticides (OCP) as well as organic-matter content. Since bulk concentrations are influenced by grain-size effects themselves, we used a novel normalization method based on the sum of concentrations in the separate grain-size fractions of the sediments. By calculating relative normalized concentrations, it was possible to clearly show underlying mechanisms throughout a heterogeneous set of samples. Furthermore, we were able to show that, for comparability, screening at <125 μm is best suited and can be further improved by additional organic-carbon normalization. 相似文献
243.
An existing model of radiocaesium transfer to grasses was extended to include wheat and barley and parameterised using data from a wide range of soils and contact times. The model structure was revised and evaluated using a subset of the available data which was not used for model parameterisation. The resulting model was then used as a basis for systematic model reduction to test the utility of the model components. This analysis suggested that the use of 4 model variables (relating to radiocaesium adsorption on organic matter and the pH sensitivity of soil solution potassium concentration) and 1 model input (pH) are not required. The results of this analysis were used to develop a reduced model which was further evaluated in terms of comparisons to observations. The reduced model had an improved empirical performance and fewer adjustable parameters and soil characteristic inputs. 相似文献
244.
Fukushima fallout in Northwest German environmental media 总被引:1,自引:0,他引:1
Traces of short- and long-lived fallout isotopes (131I, 134Cs and 137Cs) were found in environmental samples collected in Northwest Germany (rain water, river sediment, soil, grass and cow milk) from March to May 2011, following the radioactivity releases after the nuclear accident in Fukushima, Japan. The measured concentrations are consistent with reported concentrations in air, amount of rainfall and expected values applying simple radioecological models. The [134Cs]/[137Cs] ratio reported for air (about 1) allows for discrimination between “recent” and “old” 137Cs. Expected 136Cs values fell below the detection limits of the instrumentation, despite large sample masses and long counting times. 相似文献
245.
246.
该气候实验室的92.900m~3主试验箱是世界上最大和最复杂的气候环境试验箱,它采用空气补充系统以冷却或加热试验温度的空气,并将该空气吸入到试验箱内,以便喷气发动机在气候试验期间得以操作.本文讨论的其它试验设备还有2.750m~3发动机和辅助试验设备,2.125m~3太阳、风、雨和砂尘试验设备. 相似文献
247.
Trevor D.Jones 《防灾减灾工程学报》1995,(Z1)
<正> 1 地震危险性评定历史对地震,斐济人有一个专门术语,叫做“une une”,这意味着斐济的居民们长久以来就认识到该群岛是地震活动区。斐济的第一张地震图是1913年安装在首都苏瓦的米尔恩地震仪记录的。从那时起,地震记录基本上是连续的(Singh,1985)。斐济最早的地震危险性评定是由Houtz(1961)进行的,他将斐济作为一个单一的均匀活动区,直到1965~1969年间拉蒙特地质观象台在该国建立第一个由3个台站组成的台网,才开始确定地震带(Sykes等,1969;Draunidalo和Hamburger,1984)。 相似文献
248.
The impact of urbanization on timber harvesting in the south central United States was investigated. Geo-referenced Census and Forest Inventory Analysis (FIA) data were combined using a geographic information system (GIS) in order to examine the effects of various demographic and biophysical forest inventory characteristics on timber harvesting. These effects were estimated for intermediate and final harvests using a multinomial logit model. The probability for both types of harvests decreased with increasing population density, decreasing forest size, and decreasing distance to urban areas; however, the reduction in intermediate harvests was greater for each variable. Harvesting rates decreased by as much as 19% as population densities increased or distance to urban areas decreased. The results indicated that active forest management is curtailed far beyond the urban boundary. In order to model the impact of urbanization adequately, timber supply projections must also account for its impact on harvesting frequencies in surrounding areas. 相似文献
249.
Savva D Garcia-Aljaro C Lawes KP Swiergosz-Kowalewska R 《Environment international》2002,28(3):139-146
DNA probes have been developed for subsequent use in monitoring the exposure of animals to heavy metal pollution in terrestrial environments using metallothionein (MT) gene expression in the bank vole (Clethrionomys glareolus). Three different bank vole sequences were characterised corresponding to the cDNA and the genomic DNA for MT-I and the genomic DNA for MT-II. Nucleotide sequence analysis indicates that the coding sequences of the bank vole MT-I and MT-II genes exhibit a very high degree of similarity (greater than 92%) to the corresponding genes of the Chinese hamster, the mouse and the rat. In common with other mammalian MT genes, both the MT-I and MT-II genes in the bank vole are interrupted by two introns, which are at identical positions as those in other rodent MT genes; furthermore, the sizes of these introns are similar to those in other rodents with the first intron being larger than the second and those in the MT-I gene being larger than those in the MT-II gene. The predicted amino acid sequence for the proteins shows that both proteins contain 20 cysteine residues at positions identical to those in other known mammalian MTs. The availability of these DNA sequences now provides a good opportunity to investigate MT gene expression and possible gene amplification in bank voles exposed to metal pollution. 相似文献
250.