全文获取类型
收费全文 | 384篇 |
免费 | 8篇 |
国内免费 | 39篇 |
专业分类
安全科学 | 28篇 |
废物处理 | 18篇 |
环保管理 | 36篇 |
综合类 | 140篇 |
基础理论 | 52篇 |
污染及防治 | 109篇 |
评价与监测 | 26篇 |
社会与环境 | 19篇 |
灾害及防治 | 3篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 8篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 17篇 |
2016年 | 10篇 |
2015年 | 16篇 |
2014年 | 17篇 |
2013年 | 34篇 |
2012年 | 17篇 |
2011年 | 20篇 |
2010年 | 29篇 |
2009年 | 24篇 |
2008年 | 18篇 |
2007年 | 20篇 |
2006年 | 50篇 |
2005年 | 11篇 |
2004年 | 19篇 |
2003年 | 15篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 9篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 2篇 |
排序方式: 共有431条查询结果,搜索用时 718 毫秒
191.
Yao X Lau NT Fang M Chan CK 《Journal of the Air & Waste Management Association (1995)》2006,56(2):144-151
This paper presents a technique to study air pollution by combining high spatial resolution data obtained by a mobile platform and those measured by conventional stationary stations. Conventional stations provide time-series point data but cannot yield information that is distant from the sites. This can be complemented or supplemented by mobile measurements in the vicinity of the conventional sites. Together, the combined dataset yields a clearer and more precise picture of the dispersion and the transformation of pollutants in the atmosphere in a fixed time frame. Several experiments were conducted in the years 2002-2003 to track the impact of power plant plumes on ground receptors in the immediate vicinity (within a radius of 30 km) of the plants, using a combined mobile and stationary dataset. The mobile data allowed the identification of emissions from coal-fired and gas-fired power plants. Coal-fired power plants were the major source of sulfur dioxide (SO2), whereas nitrogen oxides (NOx) emitted from the gas-fired power plant played an important role in the formation of ozone (O3) at ground level. The mobile data showed that two particle size distribution regimes were detected: one had a dominant accumulation mode at 0.40-0.65 microm and the other at 0.65-1 microm. The existence of particles characterized by their mode at 0.65-1 microm and formed by in-cloud processes suggests that vehicular emissions were not the important source. Other local sources, such as power plants (elevated emission), were the likely sources, because Hong Kong does not have much manufacturing industry. 相似文献
192.
We tested the influence of limiting access to prey on larval development of the crabs Cancer magister and Hemigrapsus oregonensis by raising their Stage 1 larvae in the laboratory on different prey densities and with various periods of access to prey.
Experiments were conducted in 1995 and 1996 at the Shannon Point Marine Center in Anacortes, Washington, USA. Our results
show that crab larvae do not require continuous access to prey for optimal development nor do they appear to require light
for prey capture. Survival and duration of Stage 1 C. magister fed continuously on only one-fourth the amount of the control density of prey and those fed at the control density for only
6 h per day were the same as for larvae fed continuously at the control density (20 ml−1). Larvae with cyclic access to prey at the control density for 24 h and then starved for 72 h showed significantly lower
survival and longer instar duration to Stage 2. Experiments on Stage 1 H. oregonensis which investigated a combination of prey density, period of access to prey and light/dark conditions during feeding revealed
that survival decreased with decreasing prey density or with decreasing feeding period, but no differences were observed during
periods of limited prey availability as a function of light or dark conditions. Stage duration was not affected by reduced
prey density nor by the light/dark condition at the time of feeding, but it was prolonged when the period of access to prey
was limited. The period of access to prey did not affect the weight of Day 1 Stage 2 larvae. Larvae fed high densities of
prey for 4 h followed by 20 h of reduced-density diet exhibited the same survival and stage duration as controls that were
continuously fed high-density prey. Our results define sub-optimal diets that can be used experimentally to determine the
nutritional contributions made by naturally-occurring prey organisms during larval development in the two species. In nature,
larvae may satisfy nutritional requirements through periodic encounters with dense prey patches during vertical migrations
by day or night.
Received: 12 August 1997 / Accepted: 5 February 1998 相似文献
193.
Lethal multiple pterygium syndrome is a rare inherited disorder. Previous reports suggest that the diagnosis may be based on prenatal sonographic demonstration of severe limb flexion, absence of fetal motion, and a large cystic hygroma in the second and third trimesters. We present the sonographic features and postmortem features of a fetus with lethal multiple pterygium syndrome at 13 weeks of gestation, which shows that the condition can possibly be diagnosed in the first trimester of pregnancy. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
194.
195.
Past increase of atmospheric CO2 involves significant contributions from both fossil and biospheric sources. The latter are controversial, partly because these CO2 releases may be balanced by accelerated regrowth following clearing of some forests, while others were being converted to agricultural or other nonforest land. A simulation model was used to reconstruct changes since 1860 and project four hypothetical future scenarios of CO2 injection to 2460. Nineteen compartments and their exchanges of carbon were considered. Areal extents of tropical forests, other wooded ecosystems, and nonforests were incorporated into the model. Rapidly and slowly exchanging pools of carbon per unit area were projected by integrating income-loss differential equations numerically. Estimated cumulative releases of CO2 from fossil fuels (plus cement) near 120 Pg of carbon (1 Pg = 1015 g) from 1860 to 1970 were assumed to equal the prompt plus delayed releases due to forest clearing. Limits of exploitable forest area and biomass were evaluated and found to contribute much less future CO2 than usable fossil fuels. Ultimate release from the latter (7500±2500 Pg C) could increase atmospheric CO2 manyfold: doubling the assumed 1860 levels as early as (1) the year 2032 for assumed early fossil-use scenarios and (2) the year 2045 for late fossil-use scenarios. Depending on the poorly known parametes that were programmed to constrain the organic production rates, cumulative storage, and the response of plants and soils to enhanced atmospheric CO2, biospheric storage might reach higher levels for all scenarios than the estimates given here. However, maximizing such storage in real life would require much closer understanding and wiser management of ecosystems than history has shown. 相似文献
196.
Cui J Zhou J Yang H Peng Y He Y Chan A 《Journal of environmental monitoring : JEM》2011,13(11):3216-3221
The dry deposition of atmospheric nitrogen (including NO(2) and NH(3)) into a typical agro-ecosystem in Southeast China during 2006-2007 was estimated. Results indicated that the dry deposition velocities of NO(2) and NH(3) ranged from 0.04-0.24 cm s(-1) and 0.09-0.47 cm s(-1), respectively. The higher values appeared in the non-crop growing period. Concentrations of atmospheric NO(2) and NH(3) ranged from 24.64-104.10 μgN m(-3) and 14.40-389.6 μgN m(-3), respectively. Variation of the NH(3) mixing ratio showed a clear double-peak. NO(2) and NH(3) deposition fluxes were 74.68-80.75 kgN ha(-1), which was equivalent to 162.4 and 175.5 kg ha(-1) of urea applied in 2006-2007. The N deposition fluxes were 13.91-40.38 and 5.33-22.73 kgN ha(-1) in peanut and rice growing periods, accounting for 8.18%-40.38% and 2.13%-23.06% of N fertilizer usages, respectively. NO(2) and NH(3) deposition were significant for the red soil farmland. 相似文献
197.
Passive samplers have become more popular in their application in the measurement of airborne chemicals. For volatile organic compounds, the rate of a chemical's diffusivity is a determining factor in the quantity of the chemical being collected for a given passive sampler. While uptake rate of a chemical in the passive sampler can be determined either by collocation deployment of both active and passive samplers or use of controlled facilities such as environmental chambers, a new approach without a need for accurate active flow rate in the collocation experiment was demonstrated in this study. This approach uses chemicals of known uptake rates as references to calculate the actual flow rate of the active sampling in the collocation experiment. The active sampling rate in turn can be used in the determination of the uptake rates of all other chemicals present in the passive samplers. The advantage of such approach is the elimination of the errors in actual active sampling rate associated with low flow employed in the collocation experiment. Using this approach, passive uptake rates of more than 80 volatile organic compounds commonly present in indoor air were determined. These experimentally determined uptake rates correlate well with air diffusivity of the chemicals, indicating the regression equation describing such correlation might be useful in predicting the uptake rates of other volatile organic chemicals in indoor air based on their air diffusivity. 相似文献
198.
Shun Chih-Hsiang Yuan Tzu-Hsuen Hung Shou-Hung Yeh Yen-Po Chen Yi-Hsuan Chan Chang-Chuan 《Environmental science and pollution research international》2021,28(22):27966-27975
Environmental Science and Pollution Research - Hyperlipidemia, which is associated with certain environmental factors, is a risk factor for cardiovascular disease. Heavy metals are important... 相似文献
199.
200.
Tetraclita japonica and T. formosana are common intertidal barnacles with similar morphology, which leads to uncertainty in their species status. In the present
study, we try to elucidate the taxonomic status of the two taxa using morphology and mitochondrial control region and cytochrome
c oxidase subunit I (COI) sequences of the barnacles in their distribution range. The two taxa were found to be morphologically
similar; a diagnostic difference between them was only observed in the colour of the parietes and opercular plates. Little
genetic differentiation was detected in the control region and COI (ΦCT < 0.025 for both markers) between two taxa, but differentiation was found between the southern (Taiwan and Hong Kong) and
northern (Japan) populations of T. japonica/T. formosana, which might be the result of isolation by distance and upwelling in summer. Our data suggest that the two presently recognized
species probably represent two colour morphotypes of the same species exhibiting different geographical distribution. T. japonica is abundant in Japan and southeast coast of China, whereas T. formosana is only abundant in Taiwan. The heterogeneous environment might exert a divergent selection pressure leading to asymmetric
distribution of the two colour morphotypes. The different colours might be a result of either phenotypic plasticity adaptive
to environmental variables or genetic hitchhiking of local adaptive genotypes.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. 相似文献