全文获取类型
收费全文 | 79篇 |
免费 | 1篇 |
国内免费 | 5篇 |
专业分类
废物处理 | 2篇 |
环保管理 | 12篇 |
综合类 | 34篇 |
基础理论 | 8篇 |
污染及防治 | 28篇 |
社会与环境 | 1篇 |
出版年
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2016年 | 1篇 |
2014年 | 2篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 9篇 |
2008年 | 4篇 |
2007年 | 6篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2002年 | 2篇 |
2001年 | 1篇 |
1999年 | 8篇 |
1997年 | 1篇 |
1993年 | 1篇 |
1988年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1964年 | 2篇 |
1962年 | 5篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
1954年 | 1篇 |
1952年 | 1篇 |
1940年 | 2篇 |
1936年 | 1篇 |
1914年 | 1篇 |
1913年 | 1篇 |
排序方式: 共有85条查询结果,搜索用时 31 毫秒
31.
René Lehmann Jean Bachmann Bilgin Karaoglan Jens Lacker Glenn Lurman Christian Polleichtner Hans Toni Ratte Monika Ratte 《Environmental Sciences Europe》2018,30(1):50
Species reproduction is an important determinant of population dynamics. As such, this is an important parameter in environmental risk assessment. The closure principle computational approach test (CPCAT) was recently proposed as a method to derive a NOEC/LOEC for reproduction count data such as the number of juvenile Daphnia. The Poisson distribution used by CPCAT can be too restrictive as a model of the data-generating process. In practice, the generalized Poisson distribution could be more appropriate, as it allows for inequality of the population mean \(\mu\) and the population variance \(\sigma ^2\). It is of fundamental interest to explore the statistical power of CPCAT and the probability of determining a regulatory relevant effect correctly. Using a simulation, we varied between Poisson distribution (\(\mu =\sigma ^2\)) and generalized Poisson distribution allowing for over-dispersion (\(\mu <\sigma ^2\)) and under-dispersion (\(\mu >\sigma ^2\)). The results indicated that the probability of detecting the LOEC/NOEC correctly was \(\ge 0.8\) provided the effect was at least 20% above or below the mean level of the control group and mean reproduction of the control was at least 50 individuals while over-dispersion was missing. Specifically, under-dispersion increased, whereas over-dispersion reduced the statistical power of the CPCAT. Using the well-known Hampel identifier, we propose a simple and straight forward method to assess whether the data-generating process of real data could be over- or under-dispersed. 相似文献
32.
33.
34.
Guenther A 《Chemosphere》2002,47(8):837-844
From November 1998 to October 2000, measurements of soil respiration were performed on the Spanish plateau for two patches of non-irrigated barley, one managed with conventional tillage (CT) and the other with reduced tillage (RT). Soil CO2 flux showed seasonal variation on both patches, with an increase from March to October, peaking in May, and a decrease during the winter period by a factor of around 2. The mean value for both combined years was 2.03 and 1.70 micromol m(-2) S(-1), in the CT and RT patches, respectively. In order to analyse the influence of RT on soil CO2 flux, two tests were performed. The first one was the Kruskal-Wallis test to compare whether the differences between the medians in both patches were statistically significant. The results obtained revealed statistically significant differences during the second year, at a 85% and 95% significance level, use being made of annual data and that recorded during the period of maximum interest, March-October, respectively. The decrease in soil respiration in the RT patch was around 24%. The second test was aimed at describing and comparing the influence of soil temperature on soil CO2 flux. By using the data of both patches recorded during the first year, an empirical equation on 10-cm soil temperature was fitted and tested on the data corresponding to the second year in each of the patches. Then, a comparison between the medians of the differences between the estimated and observed values was again performed by means of the Kruskal-Wallis test. The over-prediction of the model in the RT patch, statistically significant at a 90% significance level, was roughly 23%, confirming again the decrease in soil respiration one year after this agricultural management practice had been implemented. 相似文献
35.
Nutrients and algae in some central Iowa streams. 总被引:5,自引:0,他引:5
S P Kilkus J D LaPerriere R W Bachmann 《Journal - Water Pollution Control Federation》1975,47(7):1870-1879
36.
Young Suzanne Torrey Jason Bachmann Virginie Kohn Tamar 《Food and environmental virology》2020,12(1):20-27
Food and Environmental Virology - Quantitative PCR (qPCR) is a convenient tool for monitoring virus concentrations in water and wastewater treatment trains, though it only informs about virus... 相似文献
37.
38.
白建辉 Bradly Baker Curtis Johnson 李庆军 王永峰 赵崇奖 Lee Klinger Alex Guenther Jim Greenberg 《中国环境科学》2004,24(2):0-0
2002年7月中旬利用异戊二烯通量测定系统对云南西双版纳热带森林异戊二烯的排放通量进行了连续测量,同时对光合有效辐射(PAR)、气温、湿度、风等参数进行了观测.结果表明,热带地区人工橡胶林区域湿季异戊二烯的排放有明显的日变化规律,中午前后为一天中的最大值,异戊二烯排放通量的日平均值在0.85~0.24mgC/(m2h)之间.对小时值和日平均值而言,异戊二烯的排放与PAR和气温的变化规律比较一致,但它对PAR比对气温更加敏感.不同的天气状况对异戊二烯的排放有非常明显的影响.橡胶林是一个单萜烯排放者,其单萜烯的排放速率明显依赖于PAR.橡胶林和热带雨林冠层上空异戊二烯和单萜烯的浓度也有明显的日变化规律,而且橡胶林区域的异戊二烯和单萜烯的浓度均明显高于热带雨林. 相似文献
39.
A land use database and examples of biogenic isoprene emission estimates for the state of Texas, USA
Christine Wiedinmyer Alex Guenther Mark Estes I. Wade Strange Greg Yarwood David T. Allen 《Atmospheric environment (Oxford, England : 1994)》2001,35(36):6465-6477
Using data from a variety of sources, land use and vegetation in Texas were mapped with a spatial resolution of approximately 1 km. Over 600 classifications were used to characterize the land use and land cover throughout the state and field surveys were performed to assign leaf biomass densities, by species, to the land cover classifications. The total leaf biomass densities associated with these land use classifications ranged from 0 to 556 g/m2, with the highest assigned total and oak leaf biomass densities located in central and eastern Texas. The land cover data were used as input to a biogenic emissions model, GLOBEIS2. Estimates of biogenic emissions of isoprene based on GLOBEIS2 and the new land cover data showed significant differences when compared to biogenic isoprene emissions estimated using previous land cover data and emission estimation procedures. For example, for one typical domain in eastern Texas, total daily isoprene emissions increased by 38% with the new modeling tools. These results may ultimately affect the way in which ozone and other photochemical pollutants are modeled and evaluated in the state of Texas. 相似文献
40.
Summary This study focuses on an origin of interaction mechanism of microwave radiation with nervous system—quasi-thermal field effect.
The microwave field can cause fluctuations and vibration of the charged particles and membranes in tissues. The hypothesis
is, that this phenomenon is similar to the effect caused by Brown motion initiated by temperature and results in the same
effects without rise in temperature. The electric field of 1 V/cm can introduce disturbance of the thermal equilibrium inside
a cell of 10 μm radius, which is equivalent to disturbance produced by temperature rise of 1 K. The hypothesis, that microwave
heating should cause an effect independent of the microwave modulation frequency, while field effect depends on modulation
frequency, was examined experimentally. The 450 MHz microwave radiation, modulated at 7, 14 and 21 Hz frequencies, power density
at the skin 0.16 mW/cm2, was applied. The experimental protocol consisted of two series of five cycles of the repetitive microwave exposure at fixed
modulation frequencies. Relative changes in EEG theta, alpha and beta rhythms of the group of 13 healthy volunteers were analysed.
Analysis of the experimental data shows that: (1) statistically significant changes in EEG rhythms depend on modulation frequency
of the microwave field; (2) microwave stimulation causes an increase of the EEG energy level; (3) the effect is most intense
at beta1 rhythm and higher modulation frequencies. These findings confirm the quasi-thermal origin of the effect, different
from average heating. 相似文献