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1.
The mountain chain of the Sierra Madre de Chiapas in southern Mexico is globally significant for its biodiversity and is one of the most important coffee production areas of Mexico. It provides water for several municipalities and its biosphere reserves are important tourist attractions. Much of the forest cover outside the core protected areas is in fact coffee grown under traditional forest shade. Unless this (agro)forest cover can be sustained, the biodiversity of the Sierra Madre and the environmental services it provides are at risk. We analyzed the threats to livelihoods and environment from climate change through crop suitability modeling based on downscaled climate scenarios for the period 2040 to 2069 (referred to as 2050s) and developed adaptation options through an expert workshop. Significant areas of forest and occasionally coffee are destroyed every year by wildfires, and this problem is bound to increase in a hotter and drier future climate. Widespread landslides and inundations, including on coffee farms, have recently been caused by hurricanes whose intensity is predicted to increase. A hotter climate with more irregular rainfall will be less favorable to the production of quality coffee and lower profitability may compel farmers to abandon shade coffee and expand other land uses of less biodiversity value, probably at the expense of forest. A comprehensive strategy to sustain the biodiversity, ecosystem services and livelihoods of the Sierra Madre in the face of climate change should include the promotion of biodiversity friendly coffee growing and processing practices including complex shade which can offer some hurricane protection and product diversification; payments for forest conservation and restoration from existing government programs complemented by private initiatives; diversification of income sources to mitigate risks associated with unstable environmental conditions and coffee markets; integrated fire management; development of markets that reward sustainable land use practices and forest conservation; crop insurance programs that are accessible to smallholders; and the strengthening of local capacity for adaptive resource management.  相似文献   
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The Asian Network on Climate Science and Technology (www.ancst.org), in collaboration with Tsinghua University, held a conference on environmental and climate science, air pollution, urban planning and transportation in July 2015, with over 40 Asian experts participating and presentation. This was followed by a meeting with local government and community experts on the practical conclusions of the conference. Of the papers presented at the conference a selection are included in this special issue of Journal of Environmental Science, which also reflects the conclusions of the Paris Climate meeting in Dec 2015, when the major nations of the world agreed about the compelling need to reduce the upward trend of adverse impacts associated with global climate change. Now is the time for urban areas to work out the serious consequences for their populations, but also how they should work together to take action to reduce global warming to benefit their own communities and also the whole planet!  相似文献   
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丁布的分离、纯化和结构鉴定及其对麦长管蚜   总被引:12,自引:0,他引:12  
从玉米苗中分离、纯化得到丁布,利用纸层析,紫外分光光度扫描和核磁共振^1H NMR等技术对其作结构鉴定。结果与文献报道基本一致,且纯度在96.7%以上,以纯化的丁布为标样,用HPLC方法分析了不同抗性级别的小麦品种中丁布的含量。结果表明:品种之间丁布的含量差异显著,丁布的浓度与小麦的抗蚜级别呈显著负相关,与麦长管蚜的内禀增长率rm亦呈显著负相关,借助麦长管蚜全纯人工饲料研究表明,丁布对麦长管蚜有明显的拒食性作用。图3表2参13。  相似文献   
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The Maltese top-shell, Gibbula nivosa Adams 1851, is a critically endangered marine trochid gastropod endemic to the Maltese Islands (central Mediterranean). Previously unrecorded live since 1981, rediscovery of this species in 2006 has enabled the collection of basic biological data for the first time, based on a population in Sliema Creek. The field distribution and habitat preferences of G. nivosa were investigated via stratified random sampling, while aspects of its behaviour were studied through laboratory experiments. Gibbula nivosa occurred primarily in near-homogeneous or homogeneous infralittoral cobble/pebble beds, at an overall density of 17.6 ± 25.0 SD individuals m−2; however, large spatial and temporal variations in abundance were recorded. The snails did not exhibit gregarious behaviour and the slightly clumped dispersion pattern noted in the field appeared to result from patchiness of the habitat. Recruitment was observed in post-summer months, which, together with data on shell-size distributions, suggests that G. nivosa spawns in early summer and attains adult size (maximum shell width ~9 mm) in less than 1 year. Gibbula nivosa showed a circadian activity pattern with nocturnal foraging involving indiscriminate ingestion of particles browsed off the substratum; observations on responses to four potential predators suggest that nocturnal activity may have evolved in response to diurnal predation. Historical records of snail occurrence and the present study suggest that population declines of G. nivosa in the past were probably related to habitat alteration as a result of anthropogenic pressure.  相似文献   
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To assess the concern over declining base cation levels in forest soils caused by acid deposition, input-output budgets (1990s average) for sulphate (SO4), inorganic nitrogen (NO3-N; NH4-N), calcium (Ca), magnesium (Mg) and potassium (K) were synthesised for 21 forested catchments from 17 regions in Canada, the United States and Europe. Trend analysis was conducted on monthly ion concentrations in deposition and runoff when more than 9 years of data were available (14 regions, 17 sites). Annual average SO4 deposition during the 1990s ranged between 7.3 and 28.4 kg ha−1 per year, and inorganic nitrogen (N) deposition was between 2.8 and 13.8 kg ha−1 per year, of which 41–67% was nitrate (NO3-N). Over the period of record, SO4 concentration in deposition decreased in 13/14 (13 out of 14 total) regions and SO4 in runoff decreased at 14/17 catchments. In contrast, NO3-N concentrations in deposition decreased in only 1/14 regions, while NH4-N concentration patterns varied; increasing at 3/14 regions and decreasing at 2/14 regions. Nitrate concentrations in runoff decreased at 4/17 catchments and increased at only 1 site, whereas runoff levels of NH4-N increased at 5/17 catchments. Decreasing trends in deposition were also recorded for Ca, Mg, and K at many of the catchments and on an equivalent basis, accounted for up to 131% (median 22%) of the decrease in acid anion deposition. Base cation concentrations in streams generally declined over time, with significant decreases in Ca, Mg and K occurring at 8, 9 and 7 of 17 sites respectively, which accounted for up to 133% (median 48%) of the decrease in acid anion concentration. Sulphate export exceeded input at 18/21 catchments, likely due to dry deposition and/or internal sources. The majority of N in deposition (31–100%; median 94%) was retained in the catchments, although there was a tendency for greater NO3-N leaching at sites receiving higher (<7 kg ha-1 per year) bulk inorganic N deposition. Mass balance calculations show that export of Ca and Mg in runoff exceeds input at all 21 catchments, but K export only exceeds input at 16/21 sites. Estimates of base cation weathering were available for 18 sites. When included in the mass balance calculation, Ca, Mg and K exports exceeded inputs at 14, 10 and 2 sites respectively. Annual Ca and Mg losses represent appreciable proportions of the current exchangeable soil Ca and Mg pools, although losses at some of the sites likely occur from weathering reactions beneath the rooting zone and there is considerable uncertainty associated with mineral weathering estimates. Critical loads for sulphur (S) and N, using a critical base cation to aluminium ratio of 10 in soil solution, are currently exceeded at 7 of the 18 sites with base cation weathering estimates. Despite reductions in SO4 and H+ deposition, mass balance estimates indicate that acid deposition continues to acidify soils in many regions with losses of Ca and Mg of primary concern. The U.S. Government's right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. The Canadian Crown reserves the right to retain a non-exclusive, royalty free licence in and to any copyright.  相似文献   
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An innovative biodegradation test system was developed in order to fill the current gap for cost effective and environmentally relevant tools to assess marine biodegradability. Glass beads were colonized by a biofilm in an open flow-through system of seawater with continuous pre-exposure to Linear Alkylbenzene Sulfonate (LAS) (20 μg/L). Thereafter, such colonized beads were added as inoculum in different test systems. [14C]-LAS (5–100 μg/L) was added and primary and ultimate biodegradation were assessed. The bacterial density collected on the beads (109 bact./mL beads) was ca. 3 orders of magnitude higher than the typical seawater content. The LAS mineralization lag phase duration decreased from 55 to < 1 days and the mineralization extent increased from 53 to 90% as the colonized beads volume increased from 10 to 275 mL. This is the first demonstration of marine bacteria's ability to mineralize LAS. On the opposite, less than 13% LAS was mineralized in seawater only. The colonized beads possibly enhanced the probability to encounter the full degraders' consortium in a low volume of seawater (100 mL).  相似文献   
9.
The relation among inbreeding, heterozygosity, and fitness has been studied primarily among outbred populations, and little is known about these phenomena in endangered populations. Most researchers conclude that the relation between coefficient of inbreeding estimated from pedigrees and fitness traits (inbreeding‐fitness correlations) better reflects inbreeding depression than the relation between marker heterozygosity and fitness traits (heterozygosity‐fitness correlations). However, it has been suggested recently that heterozygosity‐fitness correlations should only be expected when inbreeding generates extensive identity disequilibrium (correlations in heterozygosity and homozygosity across loci throughout the genome). We tested this hypothesis in Mohor gazelle (Gazella dama mhorr) and Iberian lynx (Lynx pardinus). For Mohor gazelle, we calculated the inbreeding coefficient and measured heterozygosity at 17 microsatellite loci. For Iberian lynx, we measured heterozygosity at 36 microsatellite loci. In both species we estimated semen quality, a phenotypic trait directly related to fitness that is controlled by many loci and is affected by inbreeding depression. Both species showed evidence of extensive identity disequilibrium, and in both species heterozygosity was associated with semen quality. In the Iberian lynx the low proportion of normal sperm associated with low levels of heterozygosity was so extreme that it is likely to limit the fertility of males. In Mohor gazelle, although heterozygosity was associated with semen quality, inbreeding coefficient was not. This result suggests that when coefficient of inbreeding is calculated on the basis of a genealogy that begins after a long history of inbreeding, the coefficient of inbreeding fails to capture previous demographic information because it is a poor estimator of accumulated individual inbreeding. We conclude that among highly endangered species with extensive identity disequilibrium, examination of heterozygosity‐fitness correlations may be an effective way to detect inbreeding depression, whereas inbreeding‐fitness correlations may be poor indicators of inbreeding depression if the pedigree does not accurately reflect the history of inbreeding. Correlaciones Heterocigosidad‐ Adaptabilidad y Depresión Endogámica en Dos Especies de Mamíferos Críticamente en Peligro  相似文献   
10.
Partial migration is considered ubiquitous among vertebrates, but little is known about the movements of oceanodromous apex predators such as sharks, particularly at their range extents. PAT-Mk10 and SPOT5 electronic tags were used to investigate tiger shark (Galeocerdo cuvier) spatial dynamics, site fidelity and habitat use off eastern Australia between April 2007 and May 2013. Of the 18 tags deployed, 15 recorded information on depth and/or temperature, and horizontal movements. Tracking times ranged between four and 408 days, with two recovered pop-up archival tags allowing 63 days of high-resolution archived data to be analysed. Overall mean proportions of time-at-depth revealed that G. cuvier spent the majority of time-at-depths of <20 m, but undertook dives as deep as 920 m. Tagged sharks occupied ambient water temperatures from 29.5 °C at the surface to 5.9 °C at depth. Deep dives (>500 m) occurred mostly around dawn and dusk, but no definitive daily dive patterns were observed. Horizontal movements were characterised by combinations of resident and transient behaviour that coincided with seasonal changes in water temperature. While the majority of movement activity was focused around continental slope waters, large-scale migration was evident with one individual moving from offshore Sydney, Australia, to New Caledonia (c. 1,800 km) in 48 days. Periods of tiger shark residency outside of Australia’s fisheries management zones highlight the potential vulnerability of the species to unregulated fisheries and the importance of cross-jurisdictional arrangements for species’ management and conservation.  相似文献   
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