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251.
Michael C. Morris 《Journal of Agricultural and Environmental Ethics》2006,19(5):495-514
Changes in attitudes toward animal welfare, with a greater emphasis on the importance of allowing animals to express normal patterns of behavior has led to an examination of the practice of keeping hens in battery cages. There is widespread scientific consensus that the conditions of confinement and the barren nature of battery cages severely restrict hens’ behavioral repertoire, and are thus detrimental to their welfare. The New Zealand Animal Welfare Act 1999, stipulates that animals must have “the opportunity to display normal patterns of behaviour.” In spite of this provision, the New Zealand government has not acted in phasing out battery cages, arguing instead that there is insufficient evidence that welfare will be improved by a phase-out. There is evidence of strong industry pressure on the government, and the use of tactics common in policy considerations where changes are resisted by powerful interests. It is important that policy processes are better managed so that welfare changes are based on both public preferences and scientific knowledge, and ways of doing this are discussed. 相似文献
252.
Measured gas emissions from four landfills in south africa and some implications for landfill design and methane recovery in semi-arid climates. 总被引:1,自引:0,他引:1
The magnitude of annual global emissions of methane from municipal solid waste landfills without landfill gas control systems implies that these landfills are significant contributors to the atmospheric load of greenhouse gases. There have been a number of field studies undertaken internationally to measure actual fluxes of methane and carbon dioxide from landfills, with a view to corroborating modelled predictions of the contribution of landfills to the global greenhouse gas budget. The vast majority of these studies have been undertaken in more temperate climates and in developed countries. This paper reports a study of landfill gas emissions from four large landfills located in the semi-arid interior of South Africa. A static accumulation chamber was used and measurements were made at each site over a period of two to three days. The results were analysed by three different methods, all of them leading to the same general conclusion that landfill gas emission rates were lower than expected. A common conclusion based on results from all four sites was that capping of landfills in semi-arid climates with low permeability covers would probably significantly retard the already low rate of waste degradation and thus gas generation. While this may be regarded as advantageous in the short term, it cannot be relied upon in perpetuity as clayey landfill covers will inevitably desiccate and crack in a semiarid environment. In addition, reasonable after-care periods for such landfills are likely to extend well beyond the currently stipulated 30-year period, and efforts to encourage energy recovery from landfills may be hampered because gas generation rates decrease as the waste dries out under conditions of minimal recharge from precipitation. A landfill cover that allows small amounts of percolation of rainfall into the waste may therefore in fact be beneficial in semiarid climates, although care would need to be taken to carefully regulate this infiltration. 相似文献
253.
This article presents the findings of a survey of farmers' markets customers in the Niagara region of Ontario, Canada. The recent growth of farmers' markets in North America and the association of these markets with local food systems development provoke examination to gain insights into consumer motivations for patronizing these markets, and to then reflect on their potential role within locally oriented and sustainable food production systems. The survey carried out on customers of three Niagara region farmers' markets corroborates previous studies that noted that socioeconomic and cultural factors such as the importance of food freshness, support of local farmers and the local farm economy, and social interaction—embeddedness—are key expressions of people's support and interest in farmers' markets. This work serves to heighten our understanding of consumer attitudes toward direct marketing via farmers' markets, yields useful speculation about these markets and their roles in sustainable local food systems progress, and also raises critical questions about such customer patronage and associated farmers' markets potential in local food system development. 相似文献
254.
Michael C. Morris 《Journal of Agricultural and Environmental Ethics》2003,16(2):187-207
In common with much of theEnglish-speaking world, New Zealandersgenerally oppose the use of animalexperimentation where there is no demonstrableand immediate benefit for human, animal, orenvironmental health. Intrusive experiments onsheep internal and external parasites publishedbetween 1996 and 2000 are reviewed, anddiscussed in relation to these publicsensibilities. A total of 16 publishedexperiments on sheep parasites involvedsurgical manipulations or other intrusiveprocedures. Some of these experiments had noshort-term application, or the only applicationwas in increasing animal production. Otherscould have been modified at some extra expenseso that they were less intrusive. Still otherswere duplications of previous work. All thesemanipulations would be unacceptable accordingto the orthodox morality of the general public.Breeding programs, rotation of grazing,``low-tech' vaccination, and in vitromodels of sheep can provide insights intopreventing parasite infestation withoutintrusive experiments. Such research protocolsshould take priority over existing programs.The results also confirm earlier reports thatanimal ethics committees are not fulfillingtheir mandated objective of acting as watchdogsfor the public. Possible changes in New Zealandanimal welfare legislation and itsinterpretation by Animal Ethics Committees arediscussed. 相似文献
255.
Robbins PS Crocker RL Nojima S Morris BD Roelofs WL Villani MG 《Die Naturwissenschaften》2003,90(11):517-520
The female-produced sex pheromone of Phyllophaga crinita (Burmeister) (Coleoptera: Scarabaeidae: Melolonthinae; the adult has no common name) is identified as methyl 2-(methylthio)benzoate. This is the first identification of a sulfur-containing, long-distance, female-produced sex attractant from any insect taxa. The root-feeding larvae of this species are serious pests in many crops in Texas and Mexico. In field tests, many P. crinita males were captured in traps baited with the authentic compound. Interestingly, a heteroatom analog, methyl 2-methoxybenzoate, also captured P. crinita males, but only at a dose 10,000 times higher than the lowest tested dose of the authentic pheromone.In memory of M.G. Villani, who died on 15 May 2001. His enthusiasm for soil-dwelling scarab beetles and contributions to their research are greatly missed. 相似文献
256.
257.
Gastrointestinal tract atresia has an incidence of 1 in 10 000 live-births, while gastric outlet obstruction comprises only approximately 1 per cent of these malformations. A prenatally diagnosed case is described, followed by a discussion regarding the diagnosis and possible associated abnormalities. 相似文献
258.
259.
A child was tentatively diagnosed as having cystic fibrosis, based on neonatal presentation with severe gastrointestinal complications; the diagnosis was not confirmed biochemically and no tissues were available for DNA analysis. The mother presented in her subsequent pregnancy, and microvillar enzyme analysis of cell-free amniotic fluid at both 18 and 20 weeks gestation gave equivocal results. The pregnancy was terminated voluntarily because of a trend towards abnormal enzyme assay results on the second amniocentesis. Retrospectively, fetal tissues were found to be homozygous for the most common mutation of the cystic fibrosis gene (AF508), which confirmed the prenatal assessment and suggested that the first infant of the couple was probably also affected by the disease. 相似文献
260.
The rate of light-saturated photosynthesis in 3 marine algae [Phaeodactylum tricornutum Bohlin, Nitzschia closterium (Ehrenberg) Smith and Dunaliella tertiolecta Butcher] varies during growth in batch culture. The photosynthetic rare declines most rapidly during growth at the higher temperatures. Because of these changes in photosynthesis rate, the previously reported enhanced photosynthetic abilities caused by growth at lower temperatures (generally interpreted as evidence for higher enzyme levels) can only be observed when measurements are made late in the exponential phase or after the onset of the stationary phase of growth. When allowance is made for the earlier peak of photosynthetic ability in cultures growing at higher temperatures, there is no evidence for adaptation to lower temperatures being caused by increased levels of the enzymes required for carbon-dioxide fixation. When the changes due to growth in batch culture are taken into account, certain effects of temperature can be recognized. the dry weight: chlorophyll ratio of all 3 algae increases with decreasing growth temperatures. For P. tricornutum and N. closterium, growth at lower temperatures reduces the cellular content of chlorophyll a, but has little effect on the chlorophyll content of D. tertiolecta. The dry weight: cell-number ratio of D. tertiolecta and P. tricornutum increases with lower growth temperatures, but growth temperature has little effect on the cell mass of N. closterium. Growth of the 3 algae at lower temperatures does not increase their ability to photosynthesize at these lower temperatures. Rather, it reduces their ability to assimilate carbon dioxide at the higher temperatures. 相似文献