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101.
We assayed maternal serum samples from 134 black and 268 white women from 16 to 18 weeks of gestation for intact human chorionic gonadotropin (hCG), and unconjugated oestriol (uE3). Serum from women with high ( ⩾ 2·5 MOMs) or low (risk for Down syndrome ⩾ 1/365) maternal serum alpha-fetoprotein (MSAFP) levels were excluded. After correcting for maternal weight, we found that median hCG levels were 16 per cent higher in black women but uE3 levels were not significantly different. These results confirm three other studies for hCG and one study for uE3. Corrections are recommended for both maternal serum hCG and AFP before calculating the risk for Down syndrome in black women. 相似文献
102.
Naoko Seino Hidetaka Sasaki Junji Sato Masaru Chiba 《Atmospheric environment (Oxford, England : 1994)》2004,38(40):7073
After severe eruptions of the volcano at Miyake Island in August 2000, a large amount of volcanic gas was released into the atmosphere. To simulate flows and dispersion of sulfur dioxide (SO2) over Miyake Island, a set of numerical models was developed. The multi-nesting method was adopted to reflect a realistic meteorological field and to sufficiently resolve the flow over the island with a diameter of 8 km. The outermost model was the Regional Spectral Model (RSM) of the Japan Meteorological Agency (JMA) with a horizontal grid size of 10 km. Finer atmospheric structure was simulated with the nonhydrostatic model jointly developed by the Meteorological Research Institute and the Numerical Prediction Division of JMA (MRI/NPD-NHM) with grid intervals of 2 km, 400 m and 100 m. Realistic topography of the island was represented in the innermost model. The Lagrangian particle method was applied to the dispersion model, which is driven by the meteorological field of the 100 m grid MRI/NPD-NHM. The random walk procedure was used to represent the turbulent diffusion. The model was verified in four cases. Simulated SO2 concentrations agreed well with observed concentrations at a monitoring station including temporal variation. Under a large synoptic change, however, accurate prediction became difficult. Further numerical experiments have been done to investigate characteristics of the flow and the distribution of SO2. Steady inflows, classified according to the surface wind speed and direction, were assumed. Simulated SO2 distribution on the ground apparently depends on the surface wind. Under relatively weak inflow, there is a large diurnal change in SO2 distribution, affected by the thermally induced flow. SO2 gas is widely spread downstream in the nighttime but hardly reaches the coastal area in the daytime. On the other hand, SO2 gas steadily reached the downstream coast with little diurnal variation under the stronger inflow. Ground temperature, as well as the static stability of the inflow, also influences downstream wind, turbulent diffusivity and SO2 distribution. 相似文献
103.
Sodic soils reclaimed with by-product from flue gas desulfurization: corn production and soil quality 总被引:16,自引:0,他引:16
Interest is growing in the use of by-product from flue gas desulfurization (FGD) to reclaim sodic soils by controlling the pH and excessive Na+. This study evaluated the effects on corn (Zea mays) production and pH and electrical conductivity (EC) of calcareous sodic soil during four times of cultivation when the by-product was applied once at the first cultivation (Study I) and the impacts on plant and soil quality at first cultivation when the by-product was applied to the soil at 23,000 kg ha-1 (Study II). In Study I, the germination rate and corn production increased by applying the by-product (0, 5,800, 11,600, and 23,100 kg ha-1), and the greatest total amounts of corn production during the four times of cultivation was when the by-product was applied at 23,100 kg ha-1. In Study II, the pH, exchangeable sodium percentage (ESP), clay dispersion and soluble Na+ in the soil decreased and soluble Mg2+ and soluble K+ in the soil increased. The soil pH was reduced from 9.0 to 7.7 by applying the by-product. However, the by-product decreased the concentrations of total N and P in corn leaves in this study. No significant difference in the concentrations of Mo, Zn, Pb, Ni, Cd, Mn, Cr, Cu, and Al in corn leaves and the soil was observed between the by-product addition and the control except for B in the soil and Fe in corn leaves. The concentration of B in the soil was reduced from 28.7 mg kg-1 to 25.4 mg kg-1 and the concentration of Fe in corn leaves increased from 17.5 mg kg-1 to 22.6 mg kg-1 by applying the by-product in our study. 相似文献
104.
105.
Ide J Chiwa M Higashi N Maruno R Mori Y Otsuki K 《Environmental monitoring and assessment》2012,184(8):4747-4762
This study sought to determine the lowest number of storm events required for adequate estimation of annual nutrient loads from a forested watershed using the regression equation between cumulative load (∑L) and cumulative stream discharge (∑Q). Hydrological surveys were conducted for 4 years, and stream water was sampled sequentially at 15-60-min intervals during 24 h in 20 events, as well as weekly in a small forested watershed. The bootstrap sampling technique was used to determine the regression (∑L-∑Q) equations of dissolved nitrogen (DN) and phosphorus (DP), particulate nitrogen (PN) and phosphorus (PP), dissolved inorganic nitrogen (DIN), and suspended solid (SS) for each dataset of ∑L and ∑Q. For dissolved nutrients (DN, DP, DIN), the coefficient of variance (CV) in 100 replicates of 4-year average annual load estimates was below 20% with datasets composed of five storm events. For particulate nutrients (PN, PP, SS), the CV exceeded 20%, even with datasets composed of more than ten storm events. The differences in the number of storm events required for precise load estimates between dissolved and particulate nutrients were attributed to the goodness of fit of the ∑L-∑Q equations. Bootstrap simulation based on flow-stratified sampling resulted in fewer storm events than the simulation based on random sampling and showed that only three storm events were required to give a CV below 20% for dissolved nutrients. These results indicate that a sampling design considering discharge levels reduces the frequency of laborious chemical analyses of water samples required throughout the year. 相似文献
106.
Z. J. U. Malley M. Taeb T. Matsumoto H. Takeya 《Environment, Development and Sustainability》2008,10(3):349-372
In Africa, the land and water resources quality are key factors for sustainable development. The degradation of the quality
of these resources leads to scarcities and conflicts, which together threaten the sustainability of rural livelihoods. This
work investigated and analysed the livelihoods conflicts over the land and water resources and their scarcities, policies
that contributed to the land and water scarcities and the livelihood conflicts and linkage of the conflicts to the resources
scarcities and degradation. Implications of degradation of the resources, development policies and livelihoods conflicts on
sustainable development are discussed. Literature study, visits and discussions, participatory assessments, observations and
questionnaire survey were used tools to collect data. Interviews of the 266 households revealed that, those experiencing the
land and water scarcities and conflicts over these resources are significantly (p < 0.001) higher than those not experiencing the scarcities and conflicts. Crop-livestock competition, over the land and water
resources causes prominent conflicts. A significant, (p < 0.05) associations of livelihoods conflicts to water shortage and period of water shortage for crop and livestock production
were found. Improved accessibility to soil and water management technologies, wildlife–livestock co-existence, recognition
of needs and land rights for pastoralists are recommended to minimize scarcities and herders versus farmers’ conflicts. 相似文献
107.
Scott Chambers Wlodek Zahorowski Kiyoshi Matsumoto Mitsuo Uematsu 《Atmospheric environment (Oxford, England : 1994)》2009,43(2):271-279
Three years of hourly atmospheric radon measurements at Sado Island (Japan) are discussed and compared with corresponding measurements at Gosan (South Korea), and Hok Tsui (China). In conjunction with back trajectory analysis, Sado radon data are used to characterise the seasonal variability in fetch regions of air masses subject to extremes of terrestrial influence. In winter, fetch regions of air masses that have experienced the greatest terrestrial influence covered southern Siberia; in summer, the terrestrial fetch was dominated by Japan; throughout the remaining months the terrestrial fetch encompassed the Korean Peninsula and far eastern China. Summer radon data are then used to estimate the radon flux from central Honshu (23.5 mBq m?2 s?1), which varied regionally between 10.6 and 47.9 mBq m?2 s?1. The Sado radon record reported here completes a 4-site, multi-year dataset of hourly radon concentrations across East Asia and the central Pacific (spanning 16° of latitude), which constitutes a unique evaluation tool for transport and mixing schemes of atmospheric and chemical transport models. 相似文献
108.
109.
Kisei Kinoshita Wang Ning Zhang Gang Andrew Tupper Naoko Iino Satoshi Hamada Satoshi Tsuchida 《Water, Air, & Soil Pollution: Focus》2005,5(3-6):89-100
Monitoring of Asian dust at two stations in Changchun, Jilin Province in northeast China, and Kagoshima, southwest Japan,
is discussed. In Changchun, interval records were made with digital and video cameras from 18 March 2003. In Kagoshima, a
web camera system to monitor volcanic clouds has been working since December 2000, which also provides data for studies of
dust. A heavy dust episode on 11 November 2002, affecting both stations, was detected using 11 and 12 μm channels of NOAA/AVHRR.
We observed dust in Changchun on 26 March, 7, 14–16 April, 1–2, 8, 10, 19 May, 8, 23 June, and 12 July in 2003. The observed
images corresponded well to NOAA/AVHRR imagery and with 8.6, 11 and 12 μm Terra/MODIS results, although conditions were too
cloudy for satellite verification in some cases. 相似文献
110.