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191.
Integrating information for better environmental decisions   总被引:1,自引:0,他引:1  
As more is learned about the complex nature and extent of environmental impacts from progressive human disturbance, scientists, policy analysts, decision makers, educators, and communicators are increasingly joining forces to develop strategies for preserving and protecting the environment. The Eco-Informa Foundation is an educational scientific organization dedicated to promoting the collaborative development and sharing of scientific information. The Foundation participated in a recent international conference on environmental informatics through a special symposium on integrating information for better environmental decisions. Presentations focused on four general themes: (1) remote sensing and data interpretation, including through new knowledge management tools; (2) risk assessment and communication, including for radioactively contaminated facilities, introduced biological hazards, and food safety; (3) community involvement in cleanup projects; and (4) environmental education. The general context for related issues, methods and applications, and results and recommendations from those discussions are highlighted here.  相似文献   
192.
Morgan R 《Disasters》1986,10(1):30-34
This article discusses the initiative of the Government of Botswana in formulating and introducing a programme to assist recovery in rural areas after the present drought period as an important aspect of the national development effort. It examines the process by which this Post Drought Recovery Programme was arrived at, its limitations, the extent of its appropriateness to longer-term factors which render rural households more vulnerable to drought, and suggests conclusions which may be drawn to inform the design of similar programmes elsewhere.  相似文献   
193.
ABSTRACT: The property rights theory of the firm is evaluated by comparing the cost structures of a sample of water agencies under two alternative modes of ownership - public and investor owned. On the basis of the sample, investor owned water agencies appear to have lower cost structures.  相似文献   
194.
195.
This study documented the range of corals, and other prey types, consumed by 20 species of butterflyfishes, which co-occur at Lizard Island, northern Great Barrier Reef, Australia. Six species (Chaetodon aureofasciatus, C. baronessa, C. lunulatus, C. plebius, C. rainfordi and C. trifascialis) fed almost exclusively on scleractinian corals, and a further eight species (C. citrinellus, C. kleinii, C. lunula, C. melannotus, C. rafflesi, C. speculum, C. ulietensis, and C. unimaculatus) took a significant proportion of their bites from corals. The other six species (C. auriga, C. ephippium, C. lineolatus, C. semeion, C. vagabundus, and Chelmon rostratus) rarely consumed coral, but fed on small discrete prey items from non-coral substrates. Coral-feeding butterflyfishes consumed a wide range of corals. Chaetodon lunulatus, for example, consumed 51 coral species from 24 different genera. However, there was up to 72% dietary overlap between coral-feeding butterflyfishes, with 11/14 species feeding predominantly on Acropora hyacinthus or Pocillopora damicornis. The most specialised corallivore, C. trifascialis, took 88% of bites from A. hyacinthus. Chaetodon trifascialis defend territories encompassing one or more colonies of A. hyacinthus, and may have prevented other species such as C. lunulatus from feeding even more extensively on this coral. This study has shown that coexistence of coral-feeding butterflyfishes occurs despite an apparent lack of partitioning of prey resources. While different coral-feeding butterflyfishes were more or less selective in their use of different coral prey, virtually all species fed predominantly on A. hyacinthus or P. damicornis.Electronic Supplementary Material Supplementary material is available for this article at  相似文献   
196.
A transmission model was devised for trichostrongyloid nematodes of saiga antelopes and domestic sheep in Kazakhstan. The framework extends previous models by including seasonal migration of saigas, contact with separate populations of sheep, and climate-driven stochasticity in herbage biomass and in the development, survival and migration onto herbage of free-living larvae. The model was parameterised for the contrasting life histories of Marshallagia, Haemonchus and Nematodirus, three important parasites of saigas and sheep in the region, and was successful at predicting broad qualitative patterns of infection dynamics in sheep and saigas. Parasite transmission between saigas and sheep was predicted to be most important for Marshallagia (from sheep to saigas in the south in winter, and onward transmission to sheep in the north in summer) and Haemonchus (from sheep in the north in summer via saigas to sheep further south in autumn). Model predictions for winter transmission of Marshallagia infection in saigas were consistent with field data, which showed that saigas culled before they have grazed the winter range carry lower burdens of this parasite than older animals. The model provides a mechanistic explanation for its predictions, which will assist hypothesis formation, and further the epidemiological basis of efforts to control parasite transmission between wildlife and livestock in both directions. A similar modelling approach could prove useful in other situations where detailed mechanistic models of parasite transmission are inappropriate in the face of parameter uncertainty and spatio-temporal variation in climate and host density. This is likely to include the majority of wildlife-parasite systems.  相似文献   
197.
Heyerdahl EK  Morgan P  Riser JP 《Ecology》2008,89(3):705-716
Our objective was to infer the climate drivers of regionally synchronous fire years in dry forests of the U.S. northern Rockies in Idaho and western Montana. During our analysis period (1650-1900), we reconstructed fires from 9245 fire scars on 576 trees (mostly ponderosa pine, Pinus ponderosa P. & C. Lawson) at 21 sites and compared them to existing tree-ring reconstructions of climate (temperature and the Palmer Drought Severity Index [PDSI]) and large-scale climate patterns that affect modern spring climate in this region (El Ni?o Southern Oscillation [ENSO] and the Pacific Decadal Oscillation [PDO]). We identified 32 regional-fire years as those with five or more sites with fire. Fires were remarkably widespread during such years, including one year (1748) in which fires were recorded at 10 sites across what are today seven national forests plus one site on state land. During regional-fire years, spring-summers were significantly warm and summers were significantly warm-dry whereas the opposite conditions prevailed during the 99 years when no fires were recorded at any of our sites (no-fire years). Climate in prior years was not significantly associated with regional- or no-fire years. Years when fire was recorded at only a few of our sites occurred under a broad range of climate conditions, highlighting the fact that the regional climate drivers of fire are most evident when fires are synchronized across a large area. No-fire years tended to occur during La Ni?a years, which tend to have anomalously deep snowpacks in this region. However, ENSO was not a significant driver of regional-fire years, consistent with the greater influence of La Ni?a than El Ni?o conditions on the spring climate of this region. PDO was not a significant driver of past fire, despite being a strong driver of modern spring climate and modern regional-fire years in the northern Rockies.  相似文献   
198.
Morgan P  Heyerdahl EK  Gibson CE 《Ecology》2008,89(3):717-728
We inferred climate drivers of 20th-century years with regionally synchronous forest fires in the U.S. northern Rockies. We derived annual fire extent from an existing fire atlas that includes 5038 fire polygons recorded from 12,070,086 ha, or 71% of the forested land in Idaho and Montana west of the Continental Divide. The 11 regional-fire years, those exceeding the 90th percentile in annual fire extent from 1900 to 2003 (>102,314 ha or approximately 1% of the fire atlas recording area), were concentrated early and late in the century (six from 1900 to 1934 and five from 1988 to 2003). During both periods, regional-fire years were ones when warm springs were followed by warm, dry summers and also when the Pacific Decadal Oscillation (PDO) was positive. Spring snowpack was likely reduced during warm springs and when PDO was positive, resulting in longer fire seasons. Regional-fire years did not vary with El Ni?o-Southern Oscillation (ENSO) or with climate in antecedent years. The long mid-20th century period lacking regional-fire years (1935-1987) had generally cool springs, generally negative PDO, and a lack of extremely dry summers; also, this was a period of active fire suppression. The climate drivers of regionally synchronous fire that we inferred are congruent with those of previous centuries in this region, suggesting a strong influence of spring and summer climate on fire activity throughout the 20th century despite major land-use change and fire suppression efforts. The relatively cool, moist climate during the mid-century gap in regional-fire years likely contributed to the success of fire suppression during that period. In every regional-fire year, fires burned across a range of vegetation types. Given our results and the projections for warmer springs and continued warm, dry summers, forests of the U.S. northern Rockies are likely to experience synchronous, large fires in the future.  相似文献   
199.
Lima M  Ernest SK  Brown JH  Belgrano A  Stenseth NC 《Ecology》2008,89(9):2594-2603
Using long-term data on two kangaroo rats in the Chihuahuan Desert of North America, we fitted logistic models including the exogenous effects of seasonal rainfall patterns. Our aim was to test the effects of intraspecific interactions and seasonal rainfall in explaining and predicting the numerical fluctuations of these two kangaroo rats. We found that logistic models fit both data sets quite well; Dipodomys merriami showed lower maximum per capita growth rates than Dipodomys ordii, and in both cases logistic models were nonlinear. Summer rainfall appears to be the most important exogenous effect for both rodent populations; models including this variable were able to predict independent data better than models including winter rainfall. D. merriami was also negatively affected by another kangaroo rat (Dipodomys spectabilis), consistent with previous experimental evidence. We hypothesized that summer rainfall influences the carrying capacity of the environment by affecting seed availability and the intensity of intraspecific competition.  相似文献   
200.
The paper describes the development role of the London Docklands Development Corporation and what sort of plan it uses. It describes the government initiative that promoted the regeneration idea and appraises the Dockland's approach. Finally, it discusses local authority involvement in the Urban Development Corporation's initiatives.  相似文献   
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