全文获取类型
收费全文 | 451篇 |
免费 | 17篇 |
国内免费 | 12篇 |
专业分类
安全科学 | 15篇 |
废物处理 | 8篇 |
环保管理 | 94篇 |
综合类 | 73篇 |
基础理论 | 115篇 |
环境理论 | 1篇 |
污染及防治 | 109篇 |
评价与监测 | 26篇 |
社会与环境 | 34篇 |
灾害及防治 | 5篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 13篇 |
2021年 | 12篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 21篇 |
2017年 | 22篇 |
2016年 | 29篇 |
2015年 | 24篇 |
2014年 | 22篇 |
2013年 | 43篇 |
2012年 | 29篇 |
2011年 | 44篇 |
2010年 | 19篇 |
2009年 | 17篇 |
2008年 | 26篇 |
2007年 | 17篇 |
2006年 | 16篇 |
2005年 | 13篇 |
2004年 | 13篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1966年 | 1篇 |
1963年 | 2篇 |
1942年 | 1篇 |
排序方式: 共有480条查询结果,搜索用时 15 毫秒
81.
Numerous studies have focussed on the relationship between female choice and the multiple exaggerated sexual traits of males.
However, little is known about the ability of males to actively enhance specific components of their display in response to
the loss of one component. We investigated the capacity of male satin bowerbirds (Ptilonorhynchus violaceus) to respond to the loss of one of their sexual signals by performing an experiment in which we removed decorations at their
bowers. We found that males compensated for decoration loss by increasing bower construction behaviour and decreasing their
latency to bower painting. These results are novel because they suggest that males can assess the quality of their own display
and make decisions about how to augment their displays. We discuss these results in the context of previous studies of mate
choice in satin bowerbirds, as both of the supplementary behaviours we observed are known correlates of male mating success. 相似文献
82.
83.
D. Alan Hansen Eric S. Edgerton Benjamin E. Hartsell John J. Jansen Navaneethakrishnan Kandasamy 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1460-1471
Abstract This paper presents an overview of a major, long-term program for tropospheric gas and aerosol research in the southeastern United States. Building on three existing ozone (O3)-focused research sites begun in mid-1992, the Southeastern Aerosol Research and Characterization Study (SEARCH) was initiated in mid-1998 as a 7-year observation and research program with a broader focus including aerosols and an expanded geographical coverage in the Southeast. The monitoring network comprises four urban-rural (or urban-suburban) site pairs at locations along the coast of the Gulf of Mexico and inland, including two moderately sized and two major urban areas (Pensacola, FL; Gulfport, MS; Atlanta, GA; and Birmingham, AL). The sites are equipped with an extensive suite of instruments for measuring particulate matter (PM), gases relevant to secondary O3 and the production of secondary aerosol particles, and surface meteorology. The measurements taken to date have added substantially to the knowledge about the temporal behavior and geographic variability of tropospheric aerosols in the Southeast. Details are presented in four papers to follow. 相似文献
84.
Federico M. San Martini J. Jason West Benjamin de Foy Luisa T. Molina Mario J. Molina Gustavo Sosa 《Journal of the Air & Waste Management Association (1995)》2013,63(6):803-815
Abstract Based on data from the 1997 Investigación sobre Materia Particulada y Deterioro Atmosférico-Aerosol and Visibility Evaluation Research (IMADA-EVER) campaign and the inorganic aerosol model ISORROPIA, the response of inorganic aerosols to changes in precursor concentrations was calculated. The aerosol behavior is dominated by the abundance of ammonia and thus, changes in ammonia concentration are expected to have a small effect on particle concentrations. Changes in sulfate and nitrate are expected to lead to proportional reductions in inorganic fine particulate matter (PM2.5). Comparing the predictions of ISORROPIA with the observations, the lowest bias and error are achieved when the aerosols are assumed to be in the efflorescence branch. Including crustal species reduces the bias and error for nitrate but does not improve overall model performance. The estimated response of inorganic PM2.5 to changes in precursor concentrations is affected by the inclusion of crustal species in some cases, although average responses are comparable with and without crustal species. Observed concentrations of particle chloride suggest that gas phase concentrations of hydrogen chloride may not be negligible, and future measurement campaigns should include observations to test this hypothesis. Our ability to model aerosol behavior in Mexico City and, thus, design control strategies, is constrained primarily by a lack of observations of gas phase precursors. Future campaigns should focus in particular on better understanding the temporal and spatial distribution of ammonia concentrations. In addition, gas phase observations of nitric acid are needed, and a measure of particle water content will allow stable versus metastable aerosol behavior to be distinguished. 相似文献
85.
Wilfried Sanchez Benjamin Piccini Jean-Marc Porcher 《Journal of environmental science and health. Part. B》2013,48(1):65-70
The aim of this study was to characterize biomarker responses in three-spined sticklebacks exposed to prochloraz (Pcz). For this purpose, adult sticklebacks were exposed for 2 weeks to prochloraz at 0, 10, 50, 100 and 500 μg/L prior to one week of depuration in clean water. At days 7, 14 and 21, several hepatic biomarkers were measured including 7-ethoxyresorufin-O-deethylase (EROD), glutathione-S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT), total glutathione (GSH) content and thiobarbituric acid reactive substances (TBARS). Pcz induced a transient increase of antioxidant enzymes and a depletion of glutathione content during the first 7 days of exposure. This study showed that EROD activity and antioxidants were disrupted in a transient manner. GST was rapidly induced in a dose-dependent manner and this induction was persistent and observed also after depuration. GST appeared as a valuable biomarker to assess the exposure to Pcz. 相似文献
86.
Enhanced sludge solubilization by microbubble ozonation 总被引:7,自引:0,他引:7
A microbubble ozonation process for enhancing sludge solubilization was proposed and its performance was evaluated in comparison to a conventional ozone bubble contactor. Microbubbles are defined as bubbles with diameters less than several tens of micrometers. Previous studies have demonstrated that microbubbles could accelerate the formation of hydroxyl radicals and hence improve the ozonation of dyestuff wastewater. The results of this study showed that microbubble ozonation was effective in increasing ozone utilization and improving sludge solubilization. For a contact time of 80 min, an ozone utilization efficiency of more than 99% was obtained using the microbubble system, while it gradually decreased from 94% to 72% for the bubble contactor. The rate of microbial inactivation was obviously faster in the microbubble system. At an ozone dose of 0.02 g O3 g−1 TSS, about 80% of microorganisms were inactivated in the microbubble system, compared with about 50% inactivation for the bubble contactor. Compared to the bubble contactor, more than two times of COD and total nitrogen, and eight times of total phosphorus content were released from the sludge into the supernatant by using the microbubble system at the same ozone dosage. The application of microbubble technology in ozonation processes may provide an effective and low cost approach for sludge reduction. 相似文献
87.
88.
研究构建了2个容积为1.1 L的好氧活性污泥反应器(即1号和2号反应器)1,号反应器每天直接通加低剂量臭氧(投加量为0.01 g O3/g TSS),不加臭氧的2号反应器作为对照平行运行,均采用每天换一次人工污水的充/排式操作。运行71 d的结果表明2,个反应器对人工污水COD的处理效果基本相同。反应器运行40 d后1,号反应器的污泥浓度比2号反应器的污泥浓度低1 400~1 700 mg/L并可稳定在8 200 mg/L,污泥减量化效果明显。低剂量臭氧的直接通加明显降低了胞内ATP浓度,并影响了微生物的抗氧化活性,2号反应器的平均超氧化物歧化酶和过氧化氢酶酶活比1号反应器分别高了24.3%和9.5%。PCR-DGGE对两反应器微生物种群的分析结果表明:Uncultured gammaproteobacteria bacteri-um、Nannocystis exedens和Uncultured actinobacterium为1号反应器的主要种群;而2号反应器的主要种群为Uncultured bacte-rium和Uncultured gammaproteobacteria bacterium。 相似文献
89.
2+ concentration. This review describes our present knowledge about the signal transduction and its fine tuning by a complex
network of Ca2+-mediated processes in vertebrate photoreceptors.
相似文献
90.
Liquid aqueous solubility (S(w,L)), octanol/water partition coefficients (K(ow)), liquid vapor pressure (P(v,L)), and Henry's law constants (H(c)) were estimated for 20 methylated naphthalenes ranging from monomethyl to tetramethylnaphthalenes. Chromatographic methods were used for the estimation. Chromatographic retention measurements were conducted for 11 reference compounds and regressions were fit between the retention indices and the physicochemical properties. HPLC octadecylsilyl column with acetonitrile/water eluent was used for the estimation of S(w,L) and K(ow). Two GC columns, HP5-MS and a more hydrophobic HP-1, were tested for the estimation of P(v,L). Measured retention indices for the methylated naphthalenes were entered to the regression equations to calculate the physicochemical properties for these compounds. Literature values, where available, were used to validate the calculated values. The method accurately estimated the physicochemical properties. Estimated S(w,L) and P(v,L) decreased with the number of methyl groups. K(ow) increased with the number of methyl groups. There was no obvious relation between H(c) and the number of methyl groups. Log S(w,L) ranged from 0.885 for 1,2,5,6-tetramethylnaphthalene to 2.269 for 1-methylnaphthalene (mmol/m(3)). Log K(ow) varied from 3.89 for 1-methylnaphthalene to 4.95 for 1,2,5,6-tetramethylnaphthalene. Log P(v,L) ranged from -0.983 for 1,2,5,6-tetramethylnaphthalene to 0.789 for 2-methylnaphthalene (Pa). Log H(c) varied from 1.03 for 1,4,5-trimethylnaphthalene to 1.73 for 2,6-dimethylnaphthalene (Pa m(3)/mol). There were no apparent effects of GC column hydrophobicity on the accuracy of the results. Estimation of S(w,L) and K(ow) based on GC retention indices was not as accurate as with HPLC. Comparison of the estimated values with values predicted by EPIWIN indicated that EPIWIN is useful in giving order-of-magnitude prediction of physicochemical properties. 相似文献