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81.
Response patterns in adult forest trees to chronic ozone stress: identification of variations and consistencies 总被引:1,自引:0,他引:1
Nunn AJ Reiter IM Häberle KH Langebartels C Bahnweg G Pretzsch H Sandermann H Matyssek R 《Environmental pollution (Barking, Essex : 1987)》2005,136(3):365-369
The responsiveness of adult beech and spruce trees to chronic O(3) stress was studied at a free-air O(3) exposure experiment in Freising/Germany. Over three growing seasons, gas exchange characteristics, biochemical parameters, macroscopic O(3) injury and the phenology of leaf organs were investigated, along with assessments of branch and stem growth as indications of tree performance. To assess response pattern to chronic O(3) stress in adult forest trees, we introduce a new evaluation approach, which provides a comprehensive, readily accomplishable overview across several tree-internal scaling levels, different canopy regions and growing seasons. This new approach, based on a three-grade colour coding, combines statistical analysis and the proficient ability of the "human eye" in pattern recognition. 相似文献
82.
Lignin samples, sub-product in the Kraft process of cellulose from eucalyptus wood, were burnt in a laboratory scale furnace at different residence temperatures and with distinct fuel-rich atmospheres. The yields of CO, CO(2), eight light hydrocarbons (methane, ethylene, ethane, propylene, acetylene, butane, etc.) and 60 semi-volatile+volatile compounds (benzene, toluene, ethylbenzene, styrene, indene, naphthalene, dibenzofuran, phenanthrene, chrysene, etc.) were determined, with nominal reactor temperatures between 800 and 1100 degrees C and residence times of the volatiles evolved and formed between 4 and 7 s. The collection of the gases and volatiles evolved was carried out with a Tedlar bag and by XAD-4 resin respectively, comparing the data obtained in both cases. The emission factor (mg/kg) of the CO was between 2500 and 90000, and under the poor-oxygen atmosphere, the emission factors of many by-toxic products were greater than 100 mg/kg. A pyrolysis run was also performed, obtaining emission factors between 30 and 3000 mg/kg, facilitating its identification. The behaviour of different compounds in the combustion runs was discussed considering three groups in accordance with their stability vs. oxygen, and two groups vs. temperature. 相似文献
83.
Angela M. White Ronald R. Swaisgood Hemin Zhang 《Behavioral ecology and sociobiology》2002,51(6):519-529
The giant panda's (Ailuropoda melanoleuca) social system is not well known, but it is clear that competition and avoidance characterizes social interaction for this solitary species throughout most of the year. Chemical communication appears to play a major role in structuring these interactions. Pandas adopt four distinct marking postures that deposit anogenital gland secretions or urine at varying heights: squat, reverse, legcock and handstand. In this experiment we tested the behavioral responses of 28 captive pandas belonging to all age-sex groups to conspecific odors placed to mimic the height of these postures. We tested three odor stimuli: male urine, and male and female glandular secretions. In all cases, pandas spent more time investigating higher odors than lower odors, suggesting that pandas place more importance on gathering information about individuals that adopt elevated postures. Pandas, particularly subadult males, also showed evidence of avoiding areas where adult male urine was deposited to mimic the handstand posture. Based on these and other findings, we propose that elevated postures in pandas may function to communicate competitive ability and possibly aggressive intent. Height of odor deposition, especially in the handstand posture, may be associated with body size, a major determinant of competitive ability. Selection may favor signalers that capitalize on the assessment activities of assessors by depositing scents to emphasize height cues. If such signals of competitive ability are used to mediate aggressive interactions, subsequent selection may favor their use only when the signaler is prepared to escalate in a contest. 相似文献
84.
Four antennae-specific proteins (AaegOBP1, AaegOBP2, AaegOBP3, and AaegASP1) were isolated from the yellow fever mosquito, Aedes aegypti and their full-length cDNAs were cloned. RT-PCR indicated that they are expressed in female and, to a lesser extent, in male antennae, but not in control tissues (legs). AaegOBP1 and AaegOBP3 showed significant similarity to previously identified mosquito odorant-binding proteins (OBPs) in cysteine spacing pattern and sequence. Two of the isolated proteins have a total of eight cysteine residues. The similarity of the spacing pattern of the cysteine residues and amino acid sequence to those of previously identified olfactory proteins suggests that one of the cysteine-rich proteins (AaegOBP2) is an OBP. The other (AaegASP1) did not belong to any group of known OBPs. Structural analyses indicate that six of the cysteine residues in AaegOBP2 are linked in a similar pattern to the previously known cysteine pairing in OBPs, i.e., Cys-24–Cys-55, Cys-51–Cys-104, Cys-95–Cys-113. The additional disulfide bridge, Cys-38–Cys-125, knits the extended C-terminal segment of the protein to a predicted 2-helix. As indicated by circular dichroism (CD) spectra, the extra rigidity seems to prevent the predicted formation of a C-terminal -helix at low pH.Electronic Supplementary Material Supplementary material is available for this article if you access the article at . A link in the frame on the left on that page takes you directly to the supplementary material. 相似文献
85.
We report a female infant noted prenatally to have an umbilical cord mass. At birth, a labial strawberry haemangioma was noted. She subsequently developed an abdominal mass which was discovered to be a proliferating haemangioma, continuous with both the labial and the umbilical stump lesions. 相似文献
86.
Median barriers separate lanes of traffic moving in opposite directions on multilane highways. Such traffic safety devices can reduce head-on collisions but also have the potential to reduce landscape permeability by impeding wildlife movements across highways. Median barriers may also increase the risk of wildlife–vehicle collisions if an animal becomes trapped or confused amid barriers searching for a place to cross. A 2002 Transportation Research Board report highlighted the need to better understand the potential impacts of highway median barriers on wildlife. This lack of information can cause significant project delays and increase transportation project costs. This study represents the first attempt in North America to bring together information about highway median and roadside barriers and wildlife and provide preliminary guidelines to balance the needs of motorist safety and wildlife movements. 相似文献
87.
88.
Philip Drake Angela Smith 《Environmental Communication: A Journal of Nature and Culture》2016,10(6):689-703
ABSTRACTThis article considers the format and cultural politics of the hugely successful UK television program Top Gear (BBC 2002–2015). It analyzes how—through its presenting team—it constructed an informal address predicated around anti-authoritarian or contrarian banter and protest masculinity. Regular targets for Top Gear presenter’s protest—curtailed by broadcast guidelines in terms of gender and ethnicity—are deflected onto the “soft” targets of government legislation on environmental issues or various forms of regulation “red tape. Repeated references to speed cameras, central London congestion charges and “excessive” signage are all anti-authoritarian, libertarian discourses delivered through a comedic form of performance address. Thus, the BBC’s primary response to complaints made about this program was to defend the program’s political views as being part of the humor. The article draws on critical discourse analysis and conversation analysis to consider how the program licensed a particular form of engagement that helped it to deflect criticisms, and considers the limits to such discursive positioning. We conclude by examining the controversies that finally led, in 2015, to the removal of the main presenter, Jeremy Clarkson, and the ending of this version of the program through the departure of the team to an on-demand online television service. 相似文献
89.
The net ecosystem carbon exchange of human-modified environments in the Australian Capital Region 总被引:2,自引:0,他引:2
Luciana Laura Porfirio Will Steffen Damian J. Barrett Sandra L. Berry 《Regional Environmental Change》2010,10(1):1-12
As part of a larger study to quantify and map ecosystem services in southeast Australia, we estimated carbon stored in biomass
and soils and the net ecosystem carbon exchange between the land surface and the atmosphere in the Australian Capital Region
(ACR). Our aim was to understand and quantify how different human-modified landscapes provide an essential ecosystem service:
the exchange and storage of carbon in the landscape. Using a remote sensing based modelling methodology, we obtained values
of Net Primary Productivity (NPP), total carbon in soil and biomass and carbon turnover from meteorological and terrain inputs
and vegetation attributes. We obtained a set of maps of NPP, total carbon (C) storage and C-turnover for the ACR. We superimposed
a land use/cover map to assign the uptake, storage and release of carbon to different land use/cover types. Our results support
the hypothesis that human-intensive land uses significantly affect the ability of terrestrial ecosystems to provide an important
ecosystem service in the form of carbon storage. 相似文献
90.
Cristina Mangia Emilio A. L. Gianicolo Antonella Bruni Maria Angela Vigotti Marco Cervino 《Environmental monitoring and assessment》2013,185(2):1719-1735
Epidemiological studies typically use monitored air pollution data from a single station or as averaged data from several stations to estimate population exposure. In industrialized urban areas, this approach may present critical issues due to the spatial complexities of air pollutants which are emitted by different sources. This study focused on the city of Taranto, which is one of the most highly industrialized cities in southern Italy. Epidemiological studies have revealed several critical situations in this area, in terms of mortality excess and short-term health effects of air pollution. The aims of this paper are to study the variability of air pollutants in the city of Taranto and to interpret the results in relation to the applicability of the data in assessing population exposure. Meteorological and pollution data (SO2, NO2, PM10), measured simultaneously and continuously during the period 2006–2010 in five air quality stations, were analyzed. Relative and absolute spatial concentration variations were investigated by means of statistical indexes. Results show significant differences among stations. The highest correlation between stations was observed for PM10 concentrations, while critical values were found for NO2. The worst values were observed for the SO2 series. The high values of 90th percentile of differences between pairs of monitoring sites for the three pollutants index suggest that mean concentrations differ by large amounts from site to site. The overall analysis supports the hypothesis that various parts of the city are differently affected by the different emission sources, depending on meteorological conditions. In particular, analysis revealed that the influence of the industrial site may be primarily identified with the series of SO2 data which exhibit higher mean concentration values and positive correlations with wind intensity when the monitoring station is downwind from the industrial site. Results suggest evaluating the population exposure to air pollutants in industrialized cities by taking into account the possible zones of influence of different emission sources. More research is needed to identify an indicator, which ought to be a synthesis of several pollutants, and take into account the meteorological variables. 相似文献