全文获取类型
收费全文 | 2368篇 |
免费 | 15篇 |
国内免费 | 25篇 |
专业分类
安全科学 | 131篇 |
废物处理 | 154篇 |
环保管理 | 134篇 |
综合类 | 229篇 |
基础理论 | 412篇 |
环境理论 | 2篇 |
污染及防治 | 929篇 |
评价与监测 | 259篇 |
社会与环境 | 150篇 |
灾害及防治 | 8篇 |
出版年
2023年 | 25篇 |
2022年 | 78篇 |
2021年 | 74篇 |
2020年 | 42篇 |
2019年 | 70篇 |
2018年 | 92篇 |
2017年 | 103篇 |
2016年 | 144篇 |
2015年 | 73篇 |
2014年 | 138篇 |
2013年 | 288篇 |
2012年 | 156篇 |
2011年 | 182篇 |
2010年 | 111篇 |
2009年 | 94篇 |
2008年 | 108篇 |
2007年 | 125篇 |
2006年 | 83篇 |
2005年 | 72篇 |
2004年 | 69篇 |
2003年 | 61篇 |
2002年 | 50篇 |
2001年 | 28篇 |
2000年 | 25篇 |
1999年 | 18篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1979年 | 2篇 |
1967年 | 2篇 |
1965年 | 3篇 |
1963年 | 4篇 |
1962年 | 5篇 |
1961年 | 4篇 |
1960年 | 3篇 |
1959年 | 2篇 |
1958年 | 2篇 |
1915年 | 1篇 |
排序方式: 共有2408条查询结果,搜索用时 210 毫秒
851.
This work aims to evaluate the effects of compost treatment of digested sewage sludge on nitrogen behavior in two soils, a Spodosol and an Oxisol soil. Digested sewage sludge was composted with sawdust and woodchips, diluting the total nitrogen to one-fourth (dry mass basis) of its original value. Then, sludge and compost were added to the two soils on an equivalent dry weight basis to consider the risk of NO3- -N leaching. Compost treatment of sewage sludge has slowed down the release of mineral-N to half in the Spodosol and to one-third in Oxisol soil. As a result, NO3- -N concentrations in soils incubated with compost were less than half of the amounts found from soils incubated with digested sludge. Estimates were made of the maximum monthly nitrate to leach from the four combinations of soil and sludge treatment. Application of digested sludge, at a higher nitrogen application rate, resulted in a higher nitrate leaching potential than application of the compost product. Soil type also played an important role, with the Oxisol having slightly higher estimated leaching potential than the Spodosol. The higher nitrate release rate in the Oxisol is counterbalanced by its higher field capacity to lessen the expected difference between the two soils. 相似文献
852.
Esteves Gisele de Fátima Bressanin Leticia Aparecida de Souza Kamila Rezende Dázio da Silva Adriano Bortolotti Mantovani José Ricardo Marques Daniele Maria Magalhães Paulo César Pasqual Moacir de Souza Thiago Corrêa 《Environmental science and pollution research international》2020,27(31):38662-38673
Environmental Science and Pollution Research - The collapse of the Fundão dam in Mariana, MG, in 2015 resulted in the overflow of more than 50 million m3 of mud containing mine tailings,... 相似文献
853.
Esther Coz Begoña Artíñano Lisa M. Clark Mark Hernandez Allen L. Robinson Gary S. Casuccio Traci L. Lersch Spyros N. Pandis 《Atmospheric environment (Oxford, England : 1994)》2010,44(32):3952-3962
Scanning electron microscopy coupled to energy-dispersive x-ray spectroscopy (SEM/EDX) was used to quantify individual bioparticles in PM2.5 samples collected during the Pittsburgh Air Quality Study. Microscopy-based estimates of primary biogenic organic aerosol (PBOA) mass were compared to carbohydrate mass associated with PM2.5. Carbohydrates show substantial seasonal variations, with higher concentrations in the spring and the fall. During the summer, carbohydrates were about 30% of the estimated PBOA concentrations, but in the winter carbohydrate concentrations often greatly exceeded the PBOA mass estimate. Spores and insect detritus were the most abundant PBOA types in the summer samples, while winter samples were comprised predominantly of a mixture of microorganisms, insect and vegetative detritus. During the summer PBOA contributed on average 6.9 ± 5.4% by mass of the PM2.5 versus 3.3 ± 1.4% of the PM2.5 mass during the winter. 相似文献
854.
Sergio Machado Corrêa Graciela Arbilla Eduardo Monteiro Martins Simone Lorena Quitério Claudinei de Souza Guimarães Luciana Vanni Gatti 《Atmospheric environment (Oxford, England : 1994)》2010,44(19):2302-2308
The fuel matrix used in Brazil is unique around the world. The intensive use of hydrated ethanol, gasohol (gasoline with 25% v/v of ethanol), compressed natural gas (CNG), and biodiesel leads to a peculiar composition of the urban atmosphere. From 1998 to 2002 an increase in formaldehyde levels was observed and since then, a reduction. This work presents a monitoring campaign that was executed from March 2004 to February 2009 by sampling at early morning on every sunny Wednesday for a total of 183 samples. The results indicate a strong reduction in formaldehyde levels from 2004 (average of 135.8 μg m?3 with SD 28.4 μg m?3) to 2009 (average of 49.3 μg m?3 with SD 27.4 μg m?3). The levels of acetaldehyde showed a slight reduction from 2004 (average of 34.9 μg m?3 with SD 8.0 μg m?3) to 2009 (average of 26.8 μg m?3 with SD 11.5 μg m?3). Comparing the results with the concurrent evolution of the fleet and of fuel composition indicates that the observed formaldehyde levels could be associated with the increase in ethanol use and in CNG use by engines with improved technology over the first converted CNG engines. Modelling studies using the OZIPR trajectory model and the SAPRC chemical mechanism indicate that formaldehyde is the main ozone precursor in Rio de Janeiro and acetaldehyde is the forth one. 相似文献
855.
Biljana Škrbić Katarzyna Szyrwińska Nataša Đurišić-Mladenović Piotr Nowicki Janina Lulek 《Environment international》2010,36(8):862-872
Principal component analysis (PCA) was applied to a data set containing the levels of indicator polychlorinated biphenyls (PCBs) in human milk of mothers living in the Wielkopolska region, Poland, in order to investigate the information captured in the PCB patterns and to elucidate the relationship between PCB concentrations in milk and donor characteristics. According to the obtained PCA results milk fat content was the most influential factor affecting the PCB levels in milk of the Wielkopolska cohort. The lifestyle data collected from the questionnaire completed by the donors appeared to have no influence on PCB concentrations in breast milk. The score plots revealed the PCB contents of milk were quite low and uniform with a few outliers, without discrimination observed either between the primipareous and secundipareous females or between donors from the urban and rural areas. Comparison of the PCB levels and profiles of human milk from the Wielkopolska region and from various European and Asian locations made by PCA reflected a generally low background exposure and indicated the possible reasons for the outlying of some samples. In order to enhance the chances of observing the relationship between donor habits and PCB levels in breast milk it was suggested that the questionnaire be redesigned to gather information about vegetable product consumption and indoor air exposure. 相似文献
856.
Bartłomiej Milanowski Janina Lulek Hans-Joachim Lehmler Izabela Kania-Korwel 《Environment international》2010,36(8):884-892
Polychlorinated biphenyls (PCBs) are present in the environment as complex mixtures, which make it challenging to identify PCB congeners that may be subject to active transport processes. Here we employ a transgenic mouse model in combination with multivariate analyses to investigate if chiral PCBs 91, 95, 132, 136, 149, 174, 176 and 183 are subject to active (enantioselective) transport by multidrug resistance (MDR) transporters. A synthetic PCB mixture containing these congeners was administered orally to female FVB or mdr1a/1b knockout mice. Due to the short half-life of chiral PCB congeners, mice were euthanized after 24 h and PCB concentrations and enantiomeric fractions were determined in selected tissues and excreta. Principal component analysis did not reveal differences between wild-type and mdr1a/1b knockout mice. However, Hotelling T2-test revealed significantly lower PCB concentrations and a more pronounced enantiomeric enrichment in the adipose tissue of mdr1a/1b knockout mice. These differences are due to higher body weights and higher fecal fat contents of mdr1a/1b knockout mice. Analysis of the enantiomeric fractions of PCBs 91, 95, 136, 149 and 174 showed a significant enantiomeric enrichment for all five congeners in wild-type and mdr1a/1b knockout mice. Overall, by studying a PCB mixture in a transgenic mouse model in combination with a multivariate data reduction approach, PCBs 91, 95, 136, 149 and 174 could be excluded as substrates of multidrug resistance transporters 1a/b. 相似文献
857.
Mietelski JW Maksimova S Szwałko P Wnuk K Zagrodzki P Błazej S Gaca P Tomankiewicz E Orlov O 《Journal of environmental radioactivity》2010,101(6):488-493
Results are presented for 137Cs, 90Sr and plutonium activity concentrations in more than 20 samples of terrestrial invertebrates, including species of beetles, ants, spiders and millipedes, collected in the highly contaminated area of the Chernobyl exclusion zone. The majority of samples were collected in Belarus, with some also collected in the Ukraine. Three other samples were collected in an area of lower contamination. Results show that seven samples exceed an activity concentration of 100 kBq/kg (ash weight - a.w.) for 137Cs. The maximum activity concentration for this isotope was 1.52 ± 0.08 MBq/kg (a.w.) determined in ants (Formica cynerea). Seven results for 90Sr exceeded 100 kBq/kg (a.w.), mostly for millipedes. Relatively high plutonium activity concentrations were found in some ants and earth-boring dung beetles. Analyses of activity ratios showed differences in transfer of radionuclides between species. To reveal the correlation structure of the multivariate data set, the Partial Least-Squares method (PLS) was used. Results of the PLS model suggest that high radiocesium activity concentrations in animal bodies can be expected mainly for relatively small creatures living on the litter surface. In contrast, high strontium activity concentrations can be expected for creatures which conduct their lives within litter, having mixed trophic habits and a moderate lifespan. No clear conclusions could be made for plutonium. 相似文献
858.
In the present work, polylactic acid, PLA, samples were degraded by hydrothermal treatment, and then their molecular weights,
crystallinity, surface charges and compositions, were determined, respectively, by using viscometry, 1H NMR, Differential Scanning Calorimetry (DSC), microelectrophoresis and Infra Red spectroscopy methods. The viscometry and
1H NMR data indicate that the molecular weight, of the polymer, decreases after the hydrothermal treatment. However, the crystalline
fractions of the PLA samples, as obtained from the DSC and X-ray data, were not altered after the hydrothermal treatment.
Furthermore, the zeta potential data, as determined by microelectrophoresis, show for both non-degraded and degraded PLA,
an increase of the polymer surface charge density with the pH of the aqueous phase. However, at acidic pH values, the surface
charge density for the degraded PLA was higher as compared to the non degraded one. These differences in surface charge densities
of the PLA samples were confirmed by Infrared study, according to which the spectra of degraded polymer show the appearance
of carboxyl groups occurring at 1,600 cm−1 at the polymer surface. 相似文献
859.
Sven D. Jelaska Toni Nikolić Lucija Šerić Jelaska Vladimir Kušan Hrvoje Peternel Goran Gužvica Zoran Major 《Environmental management》2010,45(3):616-625
Here we present the methodology used for terrestrial biodiversity analysis and site selection in Phase B of the UNDP/GEF COAST
project. The analysis was focused on the problem of biodiversity evaluation in four Croatian counties stretching from sea
level to the highest mountain in Croatia. Data on habitats, vascular flora, and fauna (mammals, birds, reptiles, amphibians,
butterflies, ground beetles, and underground invertebrates) were collected and analyzed for each of the four counties. Emphasis
was given to the richness of endangered species and the rarity of endemic species. Based on the spatial analyses of habitat,
fauna, and flora data, four to six areas were selected from each county and ranked according to their biodiversity importance.
Overlap between areas important for richness and those important for rarity was highest for data on flora (65.5%) and lowest
for data on fauna (16.7%). When different data sets were compared, the lowest overlap was between flora and fauna (17.1%)
and largest between fauna and habitats (23.9%). Simultaneous overlap among all three data sets was found in just 6.5% of the
overall selected areas. These results suggest that less specific data, with respect to taxa threat status, could better serve
as surrogate data in estimating overall biodiversity. In summary, this analysis has demonstrated that Dalmatia is a region
with a high overall biodiversity that is important in a broader European context. 相似文献
860.
Eduardo González María González-Sanchis Álvaro Cabezas Francisco A. Comín Etienne Muller 《Environmental management》2010,45(4):669-681
The structure of the floodplain forests of the Middle Ebro River (NE Spain) was examined at patch and landscape scales along
a three-step chronosequence defined according to the extent of flow regulation-induced hydrogeomorphic changes, with the ultimate
purpose of producing baseline information to guide through management and restoration plans. At patch scale, a total of 6,891
stems within 39 plots were registered for species, diameter and health status. The stem density, size class distribution,
canopy dieback and mortality were further compared by means of non-parametric tests. At landscape scale, the temporal evolution
of the area occupied by forest stands of different ages in the floodplain along the chronosequence was evaluated using four
sets of aerial photographs dated in 1927, 1957, 1981 and 2003. The within-patch structure of pioneer forests (<25–30 years old) was characterized by dense and healthy populations of pioneer species (Populus nigra, Salix alba and Tamarix spp.), but the area occupied by these forest types has progressively decreased (up to 37%) since the intensification of river
regulation (ca. 1957). In contrast, non-pioneer forests (>25–30 years old) were characterized by declining and sparse P. nigra–S. alba–Tamarix spp. stands, where late-seral species such as Ulmus minor and Fraxinus angustifolia were frequent, but only as small-size stems. At landscape scale, these type of senescent forests have doubled their surface
after river regulation was intensified. Populus alba only appeared in the oldest plots recorded (colonized before 1957), suggesting sexual regeneration failure during the last
five decades, but usually as healthy and dense stands. Based on these findings, measures principally aimed at recovering some
hydrogeomorphic dynamism are recommended to guarantee the self-sustainability of the floodplain forest ecosystem. 相似文献