首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   291篇
  免费   4篇
  国内免费   7篇
安全科学   14篇
废物处理   14篇
环保管理   20篇
综合类   32篇
基础理论   57篇
环境理论   1篇
污染及防治   100篇
评价与监测   37篇
社会与环境   25篇
灾害及防治   2篇
  2024年   1篇
  2023年   2篇
  2022年   8篇
  2021年   14篇
  2020年   6篇
  2019年   4篇
  2018年   15篇
  2017年   13篇
  2016年   14篇
  2015年   7篇
  2014年   5篇
  2013年   21篇
  2012年   19篇
  2011年   12篇
  2010年   22篇
  2009年   15篇
  2008年   23篇
  2007年   20篇
  2006年   19篇
  2005年   5篇
  2004年   11篇
  2003年   11篇
  2002年   8篇
  2001年   3篇
  2000年   3篇
  1996年   1篇
  1993年   1篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1988年   1篇
  1987年   1篇
  1985年   2篇
  1982年   1篇
  1980年   1篇
  1978年   1篇
  1964年   1篇
  1963年   1篇
  1962年   1篇
  1926年   1篇
排序方式: 共有302条查询结果,搜索用时 31 毫秒
261.
ABSTRACT

Lead (Pb), cadmium (Cd), and mercury (Hg) contents in ten species of edible mushrooms in Trako??an, Croatia were determined. In addition, the similarity between the studied species was determined by cluster analysis. The caps and stipes of the fruiting bodies were analysed separately. The analyses were carried out by inductively coupled plasma - optical emission spectrometry (ICP-OES). The greatest mean lead concentrations of 1.91 and 1.60 mg kg ?1 were determined in caps and stipes of Macrolepiota procera. The greatest mean concentrations of cadmium (3.23 and 2.24 mg kg?1) were determined in caps and stipes of Agaricus campestris and of mercury (2.56 and 2.35 mg kg?1) in Boletus edulis. In terms of the anatomical parts of the fruiting body (cap-stipe), a considerably greater concentration of the analysed elements was found in the cap for all mushroom species. According to calculated bio-concentration factors, all the examined species were found to be bio-accumulators of Cd and Hg. On the basis of the accumulation of the studied metals, great similarity of mushroom species belonging to the same genus and partial similarity of species of the same ecological affiliation was obtained by cluster analysis.  相似文献   
262.
Environmental Science and Pollution Research - We studied the toxic effects of glyphosate in vitro on HepG2 cells exposed for 4 and 24 h to low glyphosate concentrations likely to be...  相似文献   
263.
The goal of this study was to optimize the mixture of swine manure (SM) and cattle manure (CM) used in the vermicomposting process, seeking to increase the manure biodegradation rate and enhance the biomass production of both earthworms and higher plants. To achieve this goal, physico-chemical parameters were determined to assess the final compost quality after 50 days of vermicomposting. The different manure ratios used to produce the composts (C) were as follows (SM:CM, % m/m basis): C1 100:0, C2 (75:25), C3 (50:50), C4 (25:75), and C5 (0:100). In addition, the earthworm biomass and the phytoproductivity of lettuce (Lactuca sativa L.) plants grown in mixtures (1:1) of natural soil and the most viable vermicomposts were investigated. The C1 and C2 compost compositions were associated with high earthworm mortality rates. The C3 compost provided the highest mineral concentrations and C5 showed the highest lettuce yield (wet biomass). The results verify that stabilized cattle manure is an excellent substrate for the vermicomposting process and that fresh swine manure must be mixed with pre-stabilized cattle manure to ensure an optimized vermicomposting process, which must be controlled in terms of temperature and ammonia levels. It is concluded that small livestock farmers could add value to swine manure by applying the vermicomposting process, without the need for high investments and with a minimal requirement for management of the biodegradation process. These are important technical aspects to be considered when circular economy principles are applied to small farms.  相似文献   
264.
In this study we performed a non-isothermal thermogravimetric analysis on three thermoplastics—ABS, PC and PE. The Coats and Redfern method (Nature 201:68–69, 1964) was then used to approximate the kinetic parameters of each material. In addition, we performed a series of pyrolysis experiments in a batch reactor, for each plastic. The experiments were performed over the temperature range of 600–1000 °C at a constant residence time. The liquid and solid products of the pyrolysis, were collected, separated and weighted. Those products were categorized as soot, tar and char (PC only), and their relative weight to initial sample weight (DAF) was plotted against the temperature. The tar measured was exclusively medium to high molecular weight (>80 g/mol). Results revealed that relative tar and soot production, for all three materials, first increases and then decreases with temperature increase. The maximum achieved tar yields for ABS, PC and PE were at 700, 650 and 800 °C, respectively; and the maximum soot yields were at 1000, 1000, 950 °C, respectively.  相似文献   
265.
Multi-model ensemble simulations using three coupled physical-biogeochemical models were performed to calculate the combined impact of projected future climate change and plausible nutrient load changes on biogeochemical cycles in the Baltic Sea. Climate projections for 1961-2099 were combined with four nutrient load scenarios ranging from a pessimistic business-as-usual to a more optimistic case following the Helsinki Commission's (HELCOM) Baltic Sea Action Plan (BSAP). The model results suggest that in a future climate, water quality, characterized by ecological quality indicators like winter nutrient, summer bottom oxygen, and annual mean phytoplankton concentrations as well as annual mean Secchi depth (water transparency), will be deteriorated compared to present conditions. In case of nutrient load reductions required by the BSAP, water quality is only slightly improved. Based on the analysis of biogeochemical fluxes, we find that in warmer and more anoxic waters, internal feedbacks could be reinforced. Increased phosphorus fluxes out of the sediments, reduced denitrification efficiency and increased nitrogen fixation may partly counteract nutrient load abatement strategies.  相似文献   
266.
In this study, the presence of bisphenol A (BPA) in human placental and fetal liver samples collected from 1998 to 2008 was investigated to provide a more detailed analysis of the transfer of BPA across the placenta and fetal exposure to BPA. The average concentrations in placental samples were 12.6 ng g−1 for free BPA, 17.2 ng g−1 for BPA-glu, and 30.2 ng g−1 for total BPA. The highest concentrations in placental samples were 165 ng g−1 for free BPA, 178 ng g−1 for BPA-glu, and 280 ng g−1 for total BPA. Samples with higher levels of BPA-glu had higher levels of free BPA in general. Fetal age was observed to have a significant effect on BPA-glu levels in placental samples, but not on free or total BPA. The percentages of free BPA relative to total BPA for the placental samples varied considerably from 4.2% to 100%, suggesting that the ability of maternal liver and/or the placenta to conjugate BPA is highly variable during early to mid-gestation. The average concentrations in fetal liver samples were 9.02 ng g−1 for free BPA, 19.1 ng g−1 for BPA-glu, and 25.8 ng g−1 for total BPA. The highest concentrations in fetal liver samples were 37.7 ng g−1 for free BPA, 93.9 ng g−1 for BPA-glu, and 123 ng g−1 for total BPA. The percentages of free BPA level relative to total BPA for all fetal liver samples varied from 12.4% to 99.1%, indicating extensive variability in the ability of the human feto-placental unit to glucuronidate BPA.  相似文献   
267.

Objective

In this work, continuous and size-segregated aerosol measurements at Mt. Krvavec, Slovenia, during the Eyjafjallajökull volcanic eruption were performed. Based on chemical and morphological characteristics of size-segregated particles, the presence of the volcanic aerosols after long-range transport to Slovenia was to be confirmed.

Results and conclusions

Continuous measurements with the aethalometer and SMPS indicated the suspected volcanic ash plume passing over the sampling site. The aerosols collected by discrete sampling showed a chemical signature similar to the known elemental signature of the Icelandic volcanic ash. Coarse particles showed a composition typical for silicates rich in metals; in many cases also S was present. Morphological analysis showed particles with features indicative of an explosive volcanic eruption, e.g., pumice and pumice shards, glass shards, minerals, evidence of steam condensation, etc. The high sulfate concentration associated with the fine particles resulted in sulfate crystallization within the cascade impactor leading to the formation of large structures resembling a “fern”. Mass size distributions for Fe, Ti, Mn, Ca, Na, and Mg showed one primary peak (for Fe, Mn, and Ti at 2.8 μm; for Ca, Na, and Mg at ca. 4 μm), which supports the fact that most of the particles in the coarse sizes were silicates rich in metals. The size distribution of the water-soluble SO 4 2? showed a maximum peak at 0.75 μm, which also confirms the high sulfate concentration in the fine particles. Chemical and morphological characterization of aerosols collected at Mt. Krvavec indeed confirmed that volcanic ash plume passed over Slovenia.  相似文献   
268.
The objectives of the present study were to: (i) examine the in vitro dose response of rabbit spermatozoa motility to the antifertility agent gossypol (GOS) and (ii) determine whether filtered (FIL) and unfiltered (UNFIL) GOS differ in their magnitude of effect. Rabbit semen belonging to adult males (n = 5; 12–14 months) were cultured with UNFIL GOS and FIL GOS (5% solution) and subsequently diluted (1:1–7) for analysis using a Computer Assisted Semen Analyzer (CASA) system in 5 time periods (0, 60, 120, 180 and 360 minutes). At Time 0, no significant change in rabbit spermatozoa motility (MOT) and progressive motility (PROG) with GOS FIL was noted, while increases were observed with GOS UNFIL. At Time 60, weak changes were noted for MOT and PROG. After 120 minutes of culture with both GOS FIL and GOS UNFIL, MOT and PROG decreased significantly in some experimental groups. However, no differences were recorded for both the parameters at Times 180 and 360, with the exception of PROG in the GOS UNFIL category (groups A, B, E, F and G), where a significant decrease was noticed. Detailed evaluation of the distance and velocity parameters revealed reduction in all these studied markers after 60 and 120 minutes of in vitro culture with both GOS FIL and GOS UNFIL, indirectly confirming the PROG decrease. Straightness (STR), linearity (LIN), wobble (WOB), amplitude of lateral head displacement (ALH) and beat cross frequency (BCF) mostly remained unaltered at all time periods for GOS FIL, where as some minor alterations were noticed in GOS UNFIL category for STR, LIN, WOB, ALH and BCF parameters at Time 0, 60 and 120. The present study confirms the dose and time dependent alterations of rabbit spermatozoa motility parameters by GOS. The GOS dynamics in our experiment shows that rabbit spermatozoa as a biological material can indicate a GOS inhibition of motility. Obtained data for the first time indicates a higher immobilizing potential of unfiltered GOS in comparison to filtered GOS in its inhibitory action of spermatozoa motility parameters in rabbits.  相似文献   
269.
Epidemiological studies of exposure to vegetation fire smoke are often limited by the availability of accurate exposure data. This paper describes a systematic framework for retrospectively identifying the cause of air pollution events to facilitate a long, multicenter analysis of the public health effects of vegetation fire smoke pollution in Australia. Pollution events were statistically defined as any day at or above the 95th percentile of the 24-hr average concentration of particulate matter (PM). These were identified for six cities from three distinct ecoclimatic regions of Australia. The dates of each event were then crosschecked against a range of information sources, including online newspaper archives, government and research agency records, satellite imagery, and aerosol optical thickness measures to identify the cause for the excess particulate pollution. Pollution events occurred most frequently during summer for cities in subtropical and arid regions and during winter for cities in temperate regions. A cause for high PM on 67% of days examined in the city of Sydney was found, and 94% of these could be attributed to landscape fire smoke. Results were similar for cities in other subtropical and arid locations. Identification of the cause of pollution events was much lower in colder temperate regions where fire activity is less frequent. Bushfires were the most frequent cause of extreme pollution events in cities located in subtropical and arid regions of Australia. Although identification of pollution episodes was greatly improved by the use of multiple sources of information, satellite imagery was the most useful tool for identifying bushfire smoke pollution events.  相似文献   
270.
Management of the old industrial regions’ development is a very actual problem, in particular for the post-Soviet countries. It is connected with the fact that the purposes of manufacture modernization which provide employment and incomes of the population of such regions, can contradict requirements of environmental protection. Here the most different scenarios of development are possible which need to be evaluated. Usual neoclassical criteria for this purpose do not match. Therefore, in our paper, there was a task to develop such criterion which can be used for regulation of the old industrial regions’ development taking into account the environmental factor. The paper begins with construction of regional economy model. Our model based on the J. Forrester's “world model” idea, i.e. it considers the influence of environmental pollution (atmosphere, water, earth) on the population disease level, and then—on the lifetime and the human capital; the latter ones are considered as one of the most important factors of the economic growth. On the ground of this model, the consequences for realization of different scenarios of the regional economy development are estimated. To substantiate the regulation of regional economy, the criterion of sustainable development, based on the idea of simultaneous improvement of economic and ecological parameters, is offered. The main feature of the criterion offered is that, first of all, it guarantees simultaneous improvement of each of the chosen indicators of the region’s development, and, second, allows considering interests of various coalition groups by finding realistic compromises at a choice of ways of old industrial regions’ development.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号