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591.
Modeling the effects of constructed wetland on nonpoint source pollution control and reservoir water quality improvement 总被引:1,自引:0,他引:1
This article describes the integrated modeling approach for planning the size and the operation of constructed wetlands for maximizing retention of nonpoint source pollutant loads and reservoir water-quality improvement at a catchment scale.The experimental field-scale wetland systems (four sets,0.88 ha each) have been in operation since 2002,where water depth was maintained at 30–50 cm and hydraulic loading rate was at 6.3–18.8 cm/day.The wetland system was found to be adequate for treating polluted stream water with stable removal efficiency even during the winter.The integrated modeling system (modified-BASINS) was applied to the Seokmoon estuarine reservoir watershed and calibrated with monitoring data from constructed wetland,stream,and reservoir.The calibrated integrated modeling system estimated that constructing wetlands on 0.5% (about 114 ha) of the watershed area at the mouth of reservoir could reduce 11.61% and 13.49% of total external nitrogen and phosphorus loads,respectively.It also might improve the nitrogen and phosphorus concentration of the reservoir by 9.69% and 16.48%,respectively.The study suggested that about 0.1%–1.0% of the watershed area should be allocated for constructed wetland to meet specified water-quality standards for the estuarine reservoir at the polder area where land use planning is relatively less complicated. 相似文献
592.
Measurement of flow speed in the channels of novel threadlike structures on the surfaces of mammalian organs 总被引:1,自引:0,他引:1
There have been several reports on novel threadlike structures (NTSs) on the surfaces of the internal organs of rats and rabbits
since their first observation by Bonghan Kim in 1963. To confirm this novel circulatory function, it is necessary to observe
the flow of liquid through the NTS as well as the structurally corroborating channels in the NTS. In this article, we report
on the measurement of the flow speed of Alcian blue solution in the NTSs on the organ surfaces of rabbits, and we present
electron microscopic images depicting the cribrous cross-section with channels. The speed was measured as 0.3 ± 0.1 mm/s,
and the flow distance was up to 12 cm. The flow was unidirectional, and the phase contrast microscopic images showed that
the NTSs were strongly stained with Alcian blue. The ultrastructure of the NTSs revealed by cryo-scanning electron microscopy
and high-voltage electron microscopy showed that (1) there were cell-like bodies and globular clumps of matter inside the
sinus of the channel with thin strands of segregated zones which is a microscopic evidence of the liquid flow, (2) the sinuses
have wall structures surrounded with extracellular matrices of collagenous fibers, and (3) there exists a cribriform structure
of sinuses. To understand the mechanism for the circulation, a quantitative analysis of the flow speed has been undertaken
applying a simplified windkessel model. In this analysis, it was shown that the liquid flow through the NTSs could be due
to peristaltic motion of the NTS itself.
Baeckkyoung Sung and Min Su Kim contributed equally to this work. 相似文献
593.
Feigning death is a method of self-defense employed among a wide range of prey species when threatened by predator species. This paper reports on death-feigning behavior by the fire ant, Solenopsis invicta, during intraspecific aggression among neighboring fire ant workers. Days-old workers responded to aggression by death feigning, weeks-old workers responded by fleeing and months-old workers responded by fighting back. By feigning death, days-old workers were four times more likely to survive aggression than older workers. From a proximate perspective, retaliation by young workers against aggressive older workers is certain to fail. With their relatively soft exoskeleton, young workers would be prone to injury and death and unable to execute an effective attack of biting or stinging older workers with harder exoskeletons. From an ultimate perspective, death feigning allows young workers to survive and contribute to brood care and colony growth, both of which are essential to queen survival and fitness. 相似文献
594.
MiSeon Lee GeunAe Park MinJi Park JongYoon Park JiWan Lee SeongJoon Kim 《环境科学学报(英文版)》2010,22(6):826-833
This study evaluated the reduction e ect of non-point source pollution by applying best management practices (BMPs) to a 1.21 km2
small agricultural watershed using a SWAT (Soil andWater Assessment Tool) model. Two meter QuickBird land use data were prepared
for the watershed. The SWAT was calibrated and validated using daily streamflow and monthly water quality (total phosphorus (TP),
total nitrogen (TN), and suspended solids (SS)) records from 1999 to 2000 and from 2001 to 2002. The average Nash and Sutcli e
model e ciency was 0.63 for the streamflow and the coe cients of determination were 0.88, 0.72, and 0.68 for SS, TN, and TP,
respectively. Four BMP scenarios viz. the application of vegetation filter strip and riparian bu er system, the regulation of Universal
Soil Loss Equation P factor, and the fertilizing control amount for crops were applied and analyzed. 相似文献
595.
In the present study,a physically-based hydraulic modeling tool and a data-driven approach using artificial neural networks (ANNs) were evaluated for their ability to simulate the fate and transport of microorganisms in a water system.To produce reliable data,a pipe network was constructed and a series of experiments using a fecal coliform indicator (Escherichia coli 15597) was conducted.For the physically-based model,morphological (pipe size,link length,slope,etc.) and hydraulic (flow rate) conditions were used as input variables,and for ANNs,water quality parameters (conductivity,pH,and turbidity) were used.Both approaches accurately described the fate and transport of microorganisms (physically-based model: correlation coefficient (R) in the range of 0.914 – 0.977 and ANNs: R in the range of 0.949 – 0.980),with the exception of one case at a low flow rate (q = 31.56 cm 3 /sec).This study also indicated that these approaches could be complementarily utilized to assess the vulnerability of water facilities and to establish emergency plans based on hypothetical scenarios. 相似文献
596.
Disc size regulation in the brood cell building behavior of leaf-cutter bee, <Emphasis Type="Italic">Megachile tsurugensis</Emphasis> 总被引:2,自引:1,他引:1
Kim JY 《Die Naturwissenschaften》2007,94(12):981-990
The leaf-cutter bee, Megachile tsurugensis, builds a brood cell in a preexisting tunnel with leaf discs that she cuts in decreasing sizes and assembles them like a
Russian matryoshka doll. By experimentally manipulating the brood cell, it was investigated how she regulates the size of
leaf discs that fit in the brood cell’s internal volume. When the internal volume was artificially increased by removing a
bulk of leaf discs, she decreased the leaf disc size, although increasing it would have made the leaf disc more fitting in
the increased internal volume. As a reverse manipulation, when the internal volume was decreased by inserting a group of inner
layers of preassembled leaf discs to a brood cell, she decreased the leaf disc size, so that the leaf disc could fit in the
decreased internal volume. These results suggest that she uses at least two different mechanisms to regulate the disc size:
the use of some internal memory about the degree of building work accomplished in the first and of sensory feedback of dimensional
information at the construction site in the second manipulation, respectively. It was concluded that a stigmergic mechanism,
an immediate sensory feedback from the brood cell changed by the building work, alone cannot explain the details of the bee’s
behavior particularly with respect to her initial response to the first manipulation. For a more complete explanation of the
behavior exhibited by the solitary bee, two additional behavioral elements, reinforcement of building activity and processing
of dimensional information, were discussed along with stigmergy. 相似文献
597.
Jong-Beom Seo Soo-Bin Jeon Je-Young Kim Gang-Woo Lee Jong-Hyeon Jung Kwang-Joong Oh 《环境科学学报(英文版)》2012,24(3):494-498
Aqueous ammonia (NH3) solution can be used as an alternative absorption for the control of CO2 emitted from flue gases due to its high absorption capacity, fast absorption rate and low corrosion problem. The emission of CO2 from iron and steel plants requires much attention, as they are higher than those emitted from power plants at a single point source. In the present work, low concentration ammonia liquor, 9 wt.%, was used with various additives to obtain the kinetic properties using the blast furnace gas model. Although a solution with a high ammonia concentration enables high CO2 absorption efficiency, ammonium ions are lost as ammonia vapor, resulting in reduced CO2 absorption due to the lower concentration of the ammonia absorbent. To decrease the vaporization of ammonia, ethylene glycol, glycerol and glycine, which contain more than one hydroxyl radical, were chosen. The experiments were conducted at 313 K similar to the CO2 absorption conditions for the blast furnace gas model. 相似文献
598.
Kim Pingoud Tommi Ekholm Ilkka Savolainen 《Mitigation and Adaptation Strategies for Global Change》2012,17(4):369-386
A method is presented for estimating the global warming impact of forest biomass life cycles with respect to their functionally
equivalent alternatives based on fossil fuels and non-renewable material sources. In the method, absolute global warming potentials
(AGWP) of both the temporary carbon (C) debt of forest biomass stock and the C credit of the biomass use cycle displacing
the fossil and non-renewable alternative are estimated as a function of the time frame of climate change mitigation. Dimensionless
global warming potential (GWP) factors, GWPbio and GWPbiouse, are derived. As numerical examples, 1) bioenergy from boreal forest harvest residues to displace fossil fuels and 2) the
use of wood for material substitution are considered. The GWP-based indicator leads to longer payback times, i.e. the time
frame needed for the biomass option to be superior to its fossil-based alternative, than when just the cumulative balance
of biogenic and fossil C stocks is considered. The warming payback time increases substantially with the residue diameter
and low displacement factor (DF) of fossil C emissions. For the 35-cm stumps, the payback time appears to be more than 100 years
in the climate conditions of Southern Finland when DF is lower than 0.5 in instant use and lower than 0.6 in continuous stump
use. Wood use for construction appears to be more beneficial because, in addition to displaced emissions due to by-product
bioenergy and material substitution, a significant part of round wood is sequestered into wood products for a long period,
and even a zero payback time would be attainable with reasonable DFs. 相似文献
599.
Sarker Aniruddha Islam Tofazzal Bilal Muhammad Kim Jang-Eok 《Environmental science and pollution research international》2022,29(35):52857-52872
Environmental Science and Pollution Research - This pilot investigation aimed to evaluate the removal efficiency and the underlying biocatalytic pathways of immobilized fungal laccase during the... 相似文献
600.
Park Eun Ha Kim Hwajin Heo Jongbae 《Environmental science and pollution research international》2022,29(30):45248-45260
Environmental Science and Pollution Research - To investigate the causative component for certain health outcomes, the associations between the properties of ambient particles and cause-specific... 相似文献