全文获取类型
收费全文 | 119篇 |
免费 | 2篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 7篇 |
环保管理 | 14篇 |
综合类 | 6篇 |
基础理论 | 46篇 |
污染及防治 | 37篇 |
评价与监测 | 5篇 |
社会与环境 | 4篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 32篇 |
2012年 | 3篇 |
2011年 | 3篇 |
2010年 | 4篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1995年 | 4篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 19 毫秒
111.
Changing the Course of Biodiversity Conservation in the Caatinga of Northeastern Brazil 总被引:3,自引:0,他引:3
INARA R. LEAL§ JOSÉ MARIA CARDOSO DA SILVA† MARCELO TABARELLI THOMAS E. LACHER JR. ‡ 《Conservation biology》2005,19(3):701-706
Abstract: The 735,000-km2 Caatinga is a mosaic of thorn scrub and seasonally dry forests, with more than 2000 species of vascular plants, fishes, reptiles, amphibians, birds, and mammals. Endemism in these groups varies from 7% to 57%. Inappropriate land use has already caused serious environmental damage and accelerating desertification, which is currently threatening about 15% of the region. Moreover, the rich and diversified biota of the Caatinga is poorly protected: only 11 reserves (<1% of the region) are strictly protected areas. A conservation strategy for the Caatinga biota should be designed to (1) avoid further habitat loss and desertification, (2) maintain key ecological services necessary for improving the living standards of the rural population, and (3) promote the sustainable use of the region's natural resources. Implementing an effective conservation agenda for the Caatinga is not an easy task but, with creativity and consistent financial support, it should be possible to nurture this unique biome and guarantee the preservation of its rich and diversified fauna and flora, and, with this, the well-being of its rural populations. 相似文献
112.
Sylvie Lapègue Inès Ben Salah Frederico M. Batista Serge Heurtebise Lassad Neifar Pierre Boudry 《Marine Biology》2006,150(1):103-110
Despite the economic importance of oysters due to the high aquaculture production of several species, the current knowledge of oyster phylogeny and systematics is still fragmentary. In Europe, Ostrea edulis, the European flat oyster, and Ostreola stentina, the Provence oyster or dwarf oyster, are both present along the European and African, Atlantic and Mediterranean, coasts. In order to document the relationship not only between O. stentina and O. edulis, but also with the other Ostrea and Ostreola species, we performed a sequence analysis of the 16S mitochondrial fragment (16S rDNA: the large subunit rRNA-coding gene) and the COI fragment (COI: cytochrome oxidase subunit I). Oysters were sampled from populations in Portugal (two populations), Tunisia (two populations) and Morocco (one population), identified as O. stentina on the basis of shell morphological characters. Our data supported a high degree of differentiation between O. stentina and O. edulis and a close relationship between O. stentina and both Ostrea aupouria (from New Zealand) and Ostreola equestris (from Mexico Gulf/Atlantic). The status of this geographic disjunction between these closely related species is discussed. Furthermore, although identified in a separate genus Ostreola by Harry (Veliger 28:121–158, 1985), our molecular data on O. stentina, together with those available for the other two putative congeneric species, O. equestris and Ostreola conchaphila, would favour incorporation of Ostreola in Ostrea. Finally, a PCR-RFLP approach allowed the rapid identification of O. edulis and O. stentina. 相似文献
113.
Effects of the Interaction between Genetic Diversity and UV-B Radiation on Wood Frog Fitness 总被引:1,自引:0,他引:1
Abstract: Genetic diversity may buffer amphibian populations against environmental vicissitudes. We hypothesized that wood frogs ( Rana sylvatica ) from populations with lower genetic diversity are more susceptible to ultraviolet-B (UV-B) radiation than those from populations with higher diversity. We used RAPD markers to obtain genetic diversity estimates for 12 wood frog populations. We reared larval wood frogs from these populations and exposed experimental groups of eggs and larvae to one of three treatments: unfiltered sunlight, sunlight filtered through a UV-B-blocking filter (Mylar), and sunlight filtered through a UV-B-transmitting filter (acetate). In groups exposed to UV-B, larval mortality and deformity rates increased significantly, but egg mortality did not. We found a significant negative relationship between genetic diversity and egg mortality, larval mortality, and deformity rates. Furthermore, the interaction between UV-B treatment and genetic diversity significantly affected larval mortality. Populations with low genetic diversity experienced higher larval mortality rates when exposed to UV-B than did populations with high genetic diversity. This is the first time an interaction between genetic diversity and an environmental stressor has been documented in amphibians. Differences in genetic diversity among populations, coupled with environmental stressors, may help explain patterns of amphibian decline. 相似文献
114.
115.
Heraclides brasiliensis (Lepidoptera: Papilionidae) larvae feed preferably on Piperaceae, foraging successfully on leaf tissues even though species
of this contain high levels of secondary metabolites such as amides and lignans, associated with diverse biological activities
including insecticidal properties. Studies examining the metabolism of chemical constituents in Piperaceae by insects are
rare. In this study, we characterized the metabolites of 4-nerolidylcatechol (4-NC), the major constituent of Piper umbellata (Piperaceae), and E-2,3-dihydro-3-(3,4-dihydroxyphenyl)farnesoic acid, compounds from fecal material of H. brasiliensis larvae fed a diet containing only P. umbellata leaves. The biotransformed product was also detected in larval and pupal tissues. Moreover, we observed deactivation of the
toxicity of P. umbellata leaves against brine shrimp after their metabolism in H. brasiliensis larvae from a LC50 of 523.3 to 3,460.7 μg/mL. This deactivation is closely associated with the biotransformation of 4-NC to E-2,3-dihydro-3-(3,4-dihydroxyphenyl)farnesoic acid, which showed LC50 of 8.0 and >1,000 μg/mL, respectively. 相似文献
116.
Hudson Wallace Pereira Carvalho Ana P. L. Batista Peter Hammer Gustavo H. P. Luz Teodorico C. Ramalho 《Environmental Chemistry Letters》2010,8(4):343-348
Polysaccharide natural seed coat from the tree Magonia pubescens, in the form of hydrogel was used to remove metals in aqueous solution. Swelling tests indicate that seed coat presents hydrogel
behavior, with maximum water absorption of 292 g water/g. Adsorption experiments performed using Na+, Mg2+, K+, Ca2+, Cr3+, Fe3+ and Zn2+ demonstrated that the polysaccharide structure has a high capacity to extract these ions from the aqueous solution. Scanning
electron microscopy revealed significant morphological changes of the material before and after water contact. Differential
scanning calorimetry measurements indicate a signal shift of the water evaporation temperature in the material with adsorbed
zinc. X-ray photoelectron spectroscopy analysis combined with theoretical studies by the density functional theory and on
Hartree–Fock (HF) level evidence that the metallic ions were adsorbed through coordination with hydroxyl groups of polysaccharide.
In the case of Zn2+ the lowest HF energy was observed for the tetracoordination mode, where Zn2+ is coordinated by two hydroxyl groups and two water molecules. 相似文献
117.
Abstract: Populations of wolves were estimated for the states of Gujarat and Rajasthan, India, based on interviews and surveys. The wolf range is continuous. The total number of wolves in Gujarat is between 190 and 270 and in Rajasthan is between 253 and 350. Recommendations for a wolf conservation strategy include: (1) encouraging public support and education, (2) enforcing legal protection, (3) paying compensation for wolf-killed livestock, (4) conducting surveys of wolf populations and research on the dynamics of select populations, (5) protecting breeding habitats, and (6) eradicating feral dogs from wolf conservation areas. It is not too late to save the wolf if such a conservation strategy is implemented immediately. 相似文献
118.
This article summarizes and interprets estimates, by the US Bureau of Mines and others, of the availability of silver from primary and secondary sources in market economy countries. Despite conservative measurements, ample silver to support expansion of its use in industrial applications was found to exist. Supply from only portions of this resource base can be expected to respond to changes in silver demand, because factors other than price are the major determinant of the flow of silver from large segments of its resource base. 相似文献
119.
de Souza Silva Gabriela Muricy de Carvalho Batista Muniz Izabella Veloso Cristiane Martins Santos Leandro Soares de Melo Neto Biano Alves Bonomo Renata Cristina Ferreira 《Journal of Polymers and the Environment》2022,30(1):246-257
Journal of Polymers and the Environment - Starch is the main predominant food reserve in plants. Its characteristics stand out from other carbohydrates providing it with several industrial... 相似文献
120.
Fabia Barbosa Silva Alan Carlos Costa Clarice Aparecida Megguer Júlien Silva Lima Priscila Ferreira Batista Deborah Amorim Martins Gabriel Martins Almeida Marisa Domingos Caroline Müller 《环境质量管理》2021,30(3):17-25
The economic basis of the Brazilian midwest is agriculture, concentrating most of the grain production in the country. With the purpose of increasing yield, farmers have intensified land use and the use of atrazine among other pesticides, which can supposedly compromise human health and photosynthetic metabolism of plant species from Cerrado, such as Handroanthus heptaphyllus. The aim of this study was to determine experimentally the sensitivity level of H. heptaphyllus to atrazine, by measuring gas exchange, chlorophyll a fluorescence, chloroplastidic pigments, and membrane permeability. The experiment was conducted in a factorial scheme. Nine‐month‐old H. heptaphyllus plants were treated with six realistic doses of atrazine: 0, 25, 50, 100, 200, and 400 g a.i. ha–1 (corresponding to 10, 20, 40, 80, and 100% of the commercial dose recommended for corn crops, respectively), with five replications. Evaluations were performed at 12, 36, 84, 180, and 276 h after treatment application. Photosynthesis, the effective quantum yield of photosystem II, and electron transport rate were gradually reduced by the action of atrazine. On the other hand, the nonphotochemical quenching increased gradually, which indicates that this mechanism was not sufficient to avoid oxidative stress and cellular damage in H. heptaphyllus treated plants. Based on these results, we concluded that the action of the herbicide in the photosynthetic reduction occurs by the electron transport rate limitation. Therefore, H. heptaphyllus trees are at risk in Cerrado areas next to agricultural lands. 相似文献