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231.
David J. Baker Stephen T. Garnett James O'Connor Glenn Ehmke Rohan H. Clarke John C.Z. Woinarski Melodie A. McGeoch 《Conservation biology》2019,33(2):319-328
Human modification of the environment is driving declines in population size and distributional extent of much of the world's biota. These declines extend to many of the most abundant and widespread species, for which proportionally small declines can result in the loss of vast numbers of individuals, biomass, and interactions. These losses could have major localized effects on ecological and cultural processes and services without elevating a species’ global extinction risk. Although most conservation effort is directed at species threatened with extinction in the very near term, the value of retaining abundance regardless of global extinction risk is justifiable based on many biodiversity or ecosystem service metrics, including cultural services, at scales from local to global. The challenges of identifying conservation priorities for widespread and abundant species include quantifying the effects of species’ abundance on services and understanding how these effects are realized as populations decline. Negative effects of population declines may be disconnected from the threat processes driving declines because of species movements and environment flows (e.g., hydrology). Conservation prioritization for these species shares greater similarity with invasive species risk assessments than extinction risk assessments because of the importance of local context and per capita effects of abundance on other species. Because conservation priorities usually focus on preventing the extinction of threatened species, the rationale and objectives for incorporating declines of nonthreatened species must be clearly articulated, going beyond extinction risk to encompass the range of likely harmful effects (e.g., secondary extinctions, loss of ecosystem services) if declines persist or are not reversed. Research should focus on characterizing the effects of local declines in species that are not threatened globally across a range of ecosystem services and quantifying the spatial distribution of these effects through the distribution of abundance. The case for conserving abundance in nonthreatened species can be made most powerfully when the costs of losing this abundance are better understood. 相似文献
232.
Sara Dubois Nicole Fenwick Erin A. Ryan Liv Baker Sandra E. Baker Ngaio J. Beausoleil Scott Carter Barbara Cartwright Federico Costa Chris Draper John Griffin Adam Grogan Gregg Howald Bidda Jones Kate E. Littin Amanda T. Lombard David J. Mellor Daniel Ramp Catherine A. Schuppli David Fraser 《Conservation biology》2017,31(4):753-760
Human–wildlife conflicts are commonly addressed by excluding, relocating, or lethally controlling animals with the goal of preserving public health and safety, protecting property, or conserving other valued wildlife. However, declining wildlife populations, a lack of efficacy of control methods in achieving desired outcomes, and changes in how people value animals have triggered widespread acknowledgment of the need for ethical and evidence‐based approaches to managing such conflicts. We explored international perspectives on and experiences with human–wildlife conflicts to develop principles for ethical wildlife control. A diverse panel of 20 experts convened at a 2‐day workshop and developed the principles through a facilitated engagement process and discussion. They determined that efforts to control wildlife should begin wherever possible by altering the human practices that cause human–wildlife conflict and by developing a culture of coexistence; be justified by evidence that significant harms are being caused to people, property, livelihoods, ecosystems, and/or other animals; have measurable outcome‐based objectives that are clear, achievable, monitored, and adaptive; predictably minimize animal welfare harms to the fewest number of animals; be informed by community values as well as scientific, technical, and practical information; be integrated into plans for systematic long‐term management; and be based on the specifics of the situation rather than negative labels (pest, overabundant) applied to the target species. We recommend that these principles guide development of international, national, and local standards and control decisions and implementation. 相似文献
233.
Calcium concentrations were measured in supernatant amniotic fluid in order to establish whether they may be used as a marker for cystic fibrosis. No difference in values were found, whether the sample was derived from a normal pregnancy or from a pregnancy which resulted in a baby affected with cystic fibrosis. 相似文献
234.
D. J. McRae S. G. Conard G. A. Ivanova A. I. Sukhinin S. P. Baker Y. N. Samsonov T. W. Blake V. A. Ivanov A. V. Ivanov T. V. Churkina W. M. Hao K. P. Koutzenogij Nataly Kovaleva 《Mitigation and Adaptation Strategies for Global Change》2006,11(1):45-74
As part of the Russian FIRE BEAR (Fire Effects in the Boreal Eurasia Region) Project, replicated 4-ha experimental fires were
conducted on a dry Scotch pine (Pinus sylvestris)/lichen (Cladonia sp.)/feathermoss (Pleurozeum schreberi) forest site in
central Siberia. Observations from the initial seven surface fires (2000-2001) ignited under a range of burning conditions
quantified the different fuel consumption and fire behavior characteristics (e.g., rate of spread, fireline intensity, etc.)
possible in this particular forest fuel type. Experimental results and dendrochronological study of local fire history both
support the dominance of local fire regimes by low to moderate-intensity surface fires. Carbon released by the experimental
fires ranged from 4.8 to 15.4 t C ha− 1 depending on fuel conditions and fire severity. Preliminary emission data show a strong correlation between carbon dioxide
(CO2) and carbon monoxide (CO) emissions, which should facilitate accurate estimates of fire impacts on atmospheric chemistry.
Carbon concentration in smoke samples was related to fire severity. The short landscape-scale fire-return interval (50 years),
combined with typically low fire severity, in pine ecosystems of central Siberia is often associated with low tree mortality
and relatively rapid buildup of litter and understory fuels after a fire. 相似文献
235.
To describe the genetic relationship among regional populations of two commercially valuable species of marine fish, the orange roughy Hoplostethus atlanticus and the hoki Macruronus novaezelandiae, the mitochondrial (mt) DNA haplotypes of 59 individuals were defined by direct sequencing of the cytochrome b gene. Samples of orange roughy were collected on four fishing grounds around New Zealand, one off the west coast of Tasmania and one near South Africa from 1990–1991. Samples from hoki were collected on three fishing grounds around New Zealand and one off Tasmania during the same period. An average of 252 nucleotides were sequenced from each of 32 orange roughy and an average of 372 nucleotides from each of 27 hoki. Sequence variation allowed the definition of 9 unique orange roughy haplotypes and 5 hoki haplotypes. Genetic variation, as measured by both average sequence divergence and haplotype diversity, was high in the orange roughy (nucleotide diversity=0.590%, haplotype diversity=0.782) and low in the hoki (nucleotide diversity=0.076%, haplotype diversity=0.279) relative to a similar survey of the Atlantic cod, Gadus morhua. Differences in haplotype frequencies of orange roughy from New Zealand, Tasmania and South Africa were not significant, and the most common haplotype was found in similar frequencies in these three geographically distant regions. Differences in haplotype frequencies between the New Zealand and Tasmanian samples of hoki were significant, suggesting restricted gene flow between these two regions. The contrasting patterns of low but regionally subdivided genetic variation in the hoki versus high but geographically undifferentiated genetic variation in the orange roughy may be attributed to the low fecundity, slow maturation and long lifespan of the orange roughy relative to the hoki. 相似文献
236.
237.
I. R. MacDonald G. S. Boland J. S. Baker J. M. Brooks M. C. Kennicutt II R. R. Bidigare 《Marine Biology》1989,101(2):235-247
Sediment and water samples were collected by submersible in September 1986 at 16 locations on the carbonate cap overlying a conical diapir, which was formed by the upward migration of oil and gas through a subsurface fault on the continental slope off Louisiana, USA (27°47N; 91°30.4W). The biological community at the site was photographed quantitatively with still and video cameras. Rigorous spatial sampling indices were maintained so that variation in chemical parameters and in the abundance of photographed organisms could be estimated within the bounds of the study site. Concentrations of extractable organic material (EOM) ranged from 0.24 to 119.26 in the sediment samples, while methane concentrations in the water samples were from 0.037 to 66.474 M. The visible biological community was predominantly composed of the chemosynthetic tube worms (Vestimentifera) Lamellibrachia sp. and Escarpia sp., and an undescribed, methane-oxidizing mussel (Mytilidae: Bathymodiolus-like), as well as diverse non-chemosynthetic organisms. The ranked abundance of tube worms was significantly correlated (p<0.05) with the concentration of EOM in the sediment samples, while the abundance of mussels was significantly correlated (p<0.05) with the concentration of methane in the water samples. Tube worms and mussels both occurred in dense clusters; however, the clusters of mussels had a more restricted distribution within the study site than did clusters of tube worms. Both organisms were most abundant in the vicinity of the subsurface fault. 相似文献
238.
Detecting river pollution using fluorescence spectrophotometry: case studies from the Ouseburn,NE England 总被引:5,自引:0,他引:5
Baker A Inverarity R Charlton M Richmond S 《Environmental pollution (Barking, Essex : 1987)》2003,124(1):57-70
Recent advances in fluorescence spectrophotometry enable the analysis of river dissolved organic matter. We investigate the potential of detecting sewage pollution in a small, urbanised catchment. Downstream sampling highlighted a summer maximum in tryptophan fluorescence intensity during low flow. No correlation is observed between ammonia and tryptophan fluorescence intensity. In contrast, two sewage related point-pollution events had both high tryptophan fluorescence intensity and ammonia, suggesting that the summer tryptophan increase does not original from foul sewage. Sewage inputs to the river were therefore monitored at summer base flow. This demonstrated that > 10% of the rivers' discharge is provided by sewerage inputs and that these inputs could be grouped by their fluorescence and ammonia properties: (1) 'clean' storm waters with low ammonia and tryptophan intensity (2) 'grey' waters with high tryptophan intensity and low ammonia concentration, and (3) 'foul' waters with high tryptophan intensity and ammonia concentration. All three types of sewerage input occurred irrespective of flow conditions,suggesting that sewerage cross connections are occurring. 相似文献
239.
240.