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81.
The signature whistle hypothesis states that dolphins produce highly stereotyped, individually distinctive whistles when in isolation. The presence of signature whistles has been called into question by recent studies proposing that dolphins produce a shared, simple upsweep whistle when in isolation, and that whistles produced by socializing dolphins are shared across individuals and social groups. This shared repertoire hypothesis suggests that when two animals produce the same whistle type, it is due to sharing the same common repertoire rather than one animal learning to produce the whistle of another. One difference between studies supporting or denying the existence of signature whistles is the method used to classify whistle types. We examined whistle production by 17 free-ranging bottlenose dolphins while temporarily restrained. We used both a quantitative comparison technique similar to that used to support the shared repertoire hypothesis and human judges to classify whistle types and quantify similarity between types. Contrary to recent studies that emphasize shared whistles, overall whistle sharing between isolated individuals was low (25%) and a simple upsweep did not account for the most common whistle type in half of the animals. Some species of birds, bats, and primates with stable social groups use vocal learning to converge over time to one common group distinctive call type. We examined whistle similarity between adult male dolphins that are partners in a close social alliance in order to test whether vocal learning may enable a similar vocal convergence. Whistle similarity was rated very high between partners and low between non-partners by both the quantitative technique and human observers. This suggests that as in songbirds and some other mammals, adult male bottlenose dolphins may use vocal learning to converge on similar whistles as they develop affiliative social relationships.Communicated by G. Wilkinson  相似文献   
82.
In the terrestrial environment, standardized protocols are available for measuring the exposure and effects of contaminants to invertebrates, but none currently exist for vertebrates. In an effort to address this, we proposed that developing lizard embryos may be used as a terrestrial vertebrate model. Lizard eggs may be particularly susceptible to soil contamination and in ovo exposure may affect hatchling size, mortality, as well as thyroid function. Toxicant-induced perturbations of thyroid function resulting from in ovo chemical exposure may result in toxicity during the critical perinatal period in reptiles. Fertilized Eastern fence lizard (Sceloporus undulatus) eggs were placed in cadmium (Cd)-spiked expanded perlite (0, 1.48, 14.8, 148, 1480, 14 800 μg Cd/g, nominal concentrations), artificially incubated at 28 °C, and examined daily for mortality. Whole lizard hatchlings as well as failed hatches were homogenized in ethanol and the homogenate was divided for Cd body residue analysis and thyroid hormone (triiodothyronine (T3) and thyroxine (T4)) analyses. Acute mortality was observed in the two highest doses (1480 and 14 800 μg Cd/g). Cadmium body residues showed a higher internal concentration with increasing exposure concentration indicating uptake of Cd. There was a decrease in T3:T4 ratio at the highest surviving dose (148 μg Cd/g), however, there were no differences observed in hatchling size measured as weight and snout-vent length, or in whole body thyroid hormone levels. In summary, this study has shown Cd amended to a solid phase representing soil (perlite) can traverse the thin, parchment-like shell membrane of the fence lizard egg and bioaccumulate in lizard embryos. We believe this study is a good first step in investigating and evaluating this species for use as a model.  相似文献   
83.
Scanning electron microscopy, surface area determination, elemental analysis, organic matter extraction and solid-state cross polarization/magic angle spinning and Bloch decay/magic angle spinning 13C nuclear magnetic resonance (NMR) spectroscopy were used to investigate distinctive features among carbonaceous combustion residues. Black carbon (BC) samples included diesel soot, urban dust, carbon black, chimney soot, vegetation fire residues, wood and straw charcoals. Particles varied from small spheres (<50 nm) in fossil BC (>100 m(2)/g), to large layered structures in plant-derived BC (generally <8 m(2)/g). Chimney soot also included large (>1 micrometer) liquid-like structures, while spherules >100 nm were unique to urban dust. The ratios of amorphous to soot carbon (SC) (isolated by thermal degradation) were not necessarily correlated with the degree of aromaticity estimated from H/C ratios. In particular, values of SC in diesel soot were clearly overestimated. Solvent-extractable organic matter (SEOM) was <2% for charcoals and carbon black, but >13% for urban dust, chimney and diesel soot. SEOM is thought to clog pores or to form large waxy globules, hence reducing surface areas. The ratio of polar/nonpolar SEOM was generally <7 for fossil BC, but >30 for plant-derived BC. NMR analysis revealed essentially one chemical shift in the aromatic C region of charcoals, while diesel soot also showed important aliphatic contributions. Aliphatic and oxygenated C predominated over aryl C in urban dust and chimney soot. These morphological and chemical characteristics of the BC samples are discussed in terms of their environmental implications.  相似文献   
84.
Environmental pollution with polycyclic aromatic hydrocarbons (PAHs) from pyrogenic or petrochemical sources is a matter of concern in many aquatic ecosystems. For field monitoring purposes, PAH metabolite levels in fish bile samples can be used as biomarkers of exposure, but previously there were no reference materials for analytical method validation or quality control. In this paper we describe the preparation and certification of two fish bile materials. BCR 720 is a pure bile material from sediment-exposed flounder (Platichthys flesus) and BCR 721 is a pure bile material from oil-exposed plaice (Pleuronectes platessa). Homogeneity and stability tests were carried out and a group of 12 expert laboratories was assembled for the certification measurements. The methods applied were liquid chromatography with fluorescence detection or gas chromatography with mass spectrometric detection. In BCR 720 three PAH metabolites were certified: 1-hydroxyphenanthrene, 1-hydroxypyrene and 3-hydroxybenzo[a]pyrene. In BCR 721 1-hydroxypyrene was certified. The fourth target compound, 2-hydroxynaphthalene, could not be certified, but the results obtained are listed. The major findings from earlier feasibility studies and recommendations for the optimal use of the reference materials are also included.  相似文献   
85.
Integrating protected area management with local needs and aspirations   总被引:4,自引:0,他引:4  
Wells MP  McShane TO 《Ambio》2004,33(8):513-519
Conservationists recognize that many protected areas have limited future prospects without the cooperation and support of local people, especially in developing countries. Since the 1980s Integrated Conservation and Development Projects (ICDPs) have attempted to reconcile park management with local needs and aspirations, usually with disappointing results. Achieving local cooperation and support without jeopardizing conservation goals remains a top priority for parks, however. Fortunately, the lessons from the ICDP experience provide an important opportunity to inform the next generation of biodiversity conservation programs, including those concerned with poverty alleviation as well as those working at ecosystem and landscape scales. More recent and more promising approaches have started to incorporate elements of adaptive management, new partnership models with stakeholders and the vertical integration of site-level work with policy initiatives and institutional development.  相似文献   
86.
Environmental Management - Widespread human development has led to impairment of freshwater coastal wetlands and embayments, which provide critical and unique habitat for many freshwater fish...  相似文献   
87.
To detect effects of pesticides on non-target freshwater organisms the Species at risk (SPEARpesticides) bioindicator based on biological traits was previously developed and successfully validated over different biogeographical regions of Europe using species-level data on stream invertebrates. Since many freshwater biomonitoring programmes have family-level taxonomic resolution we tested the applicability of SPEARpesticides with family-level biomonitoring data to indicate pesticide effects in streams (i.e. insecticide toxicity of pesticides). The study showed that the explanatory power of the family-level SPEAR(fm)pesticides is not significantly lower than the species-level index. The results suggest that the family-level SPEAR(fm)pesticides is a sensitive, cost-effective, and potentially European-wide bioindicator of pesticide contamination in flowing waters. Class boundaries for SPEARpesticides according to EU Water Framework Directive are defined to contribute to the assessment of ecological status of water bodies.  相似文献   
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There is increasing interest in the use of preimplantation genetic diagnosis (PGD) as an alternative to routine prenatal diagnosis. However, the costs associated with development and testing of new PGD protocols have forced some PGD centres to limit the number of diseases for which PGD is offered. One of the main factors in the design of new protocols, which affects cost and accuracy, is the choice of the mutation-detection technique. We have assessed the reliability of DNA sequencing and mini-sequencing for clinical diagnosis at the single-cell level and have found them to be rapid and accurate. Extensive optimisation for individual mutations is not usually necessary when employing these versatile techniques and consequently a smaller investment of time and resources should be required during development of new protocols. Additionally, we report single-cell protocols for the diagnoses of cystic fibrosis, sickle cell anaemia and β-thalassaemia, which utilise mini-sequencing. Unlike most mutation-detection techniques, mini-sequencing permits analysis of very small DNA fragments. Small amplicons experience low allele dropout (ADO) rates, and consequently this approach could potentially improve the reliability of PGD. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
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