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491.
Summary It has been shown in recent surveys, that in India there is an upward trend in the area of open forest, which has grown from 10.06 million ha to 26.32 million ha in a few years. But the closed forests of India have registered a fall from 36.02 million ha to around 33 million ha. The latter fact is both significant and disturbing. It proves that in spite of the Forest Conservation Act, 1980, the process of degeneration of forests, in India, constantly continues. It is obvious that a part of the open forests must have come from closed forests due to the reckless denudation of forests, carried out in the name of development. A massive afforestation/reforestation programme is desired to achieve the target of one third of the geographical area of the country to be under forest cover for proper ecological balance. India has to develop a sound National Forest Policy to meet the requirements of the country, to produce industrial wood, for forest based industries, defence, communication and other public purposes, and small timbers fuel wood and fodder for the rural community. In this context the decision taken by the Control Board of Forestry in December, 1987, is quite encouraging. It was resolved that the extraction of wood from the forests would be stopped and the country's need for timber and fuelwood would be met by importing wood and by means of farm forestry. The reconstitution of the National Wasteland Development Board and the planting target of 5 million ha p.a. are other positive steps in this direction. Extensive research is needed for a better and new approach to social and commercial forestry.Dr Om Prasad, the senior author, is a biologist in the Department of Zoology, University of Allahabad. He is responsible for developing a number of Environmental Biology Courses at graduate and post-graduate level. Besides being actively engaged in research on the adverse toxilogical effects of a number of commonly used food additives, he supports environmental protection activities including the provision of guidance to the Students Nature Club which is affiliated to WWF-India.Dr Pawan Kumar, after teaching for seven years in the Department of Forestry at Birsa Agricultural University, Ranchi, Bihar, recently joined the Department of Environment of the Government of India where he is in charge of a number of environmental projects. Dr O.N. Pandey is a specialist in Forestry teaching at Birsa Agricultural University, India.  相似文献   
492.
493.
In recent years, churches across the world have become involved in dialogue on the theory and practice of sustainable development. A number of Western churches have expressed their concern about climate change and destructive living patterns, stressing the need for human beings to exercise the care for all creation based on a life of sharing and sacrifice. Some Orthodox churches, however, quite recently included the environmental issues in their agendas. While the Bases of Social Concept, a major doctrine of the Russian Orthodox Church adopted in 2000, for the first time emphasises the Churchs position in overcoming environmental crisis and presents a solid basis on which to build the future environmental strategy of the Church, the Ethiopian Orthodox Church has not yet drawn up a programme document that might serve as a framework for the Churchs current extensive activities in the field of biodiversity conservation and sustainable forestry practices. Hence, despite certain closeness of both institutions, there is the potential for strengthening their roles in promoting sustainable development, based on the Biblical concept that the Earth belongs to the Lord and humans are responsible stewards assigned the duty to work for creation and care for it. This paper seeks to demonstrate by means of comparable analysis between the two Churches, Orthodox in nature but different in rites and religious practices, that traditional, highly conservative faiths may serve as powerful instruments of spreading out the ideas of sustainable development as the basis of spiritual revival in the situation of the two concurrent and interrelated crises – spiritual and ecological.Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
494.
Food production has to be increased in a sustainable way to meet the future global demand. A key position is attributed to developing countries. A deepened understanding of their agricultural regions with specific resource endowments and constraints is therefore crucial. In this study we propose a methodology based on material flux analysis (MFA) to assess the resource potentials and limitations of a Nicaraguan agricultural region. We focus on current regional and farm resource management and explore them under two scenarios. Indicators are nitrogen and the degrees of self-sufficiency (DSS) for energy, and the staples maize and beans. As data is scarce, most information is based on interviews with farmers of four categories and key persons, and on literature. The results show that nitrogen management does not differ considerably among categories. Nitrogen is mined mostly from staple plots. Self-sufficiency for beans is given in an average year. Yet, landless and small farmers neither produce enough maize for autoconsumption, nor are they self-sufficient for firewood. Energy supply is also the core problem of the region, since the DSS is 70%. Soil nitrogen stocks last at most for three more generations. Analyses with the scenario technique show that: (a) Unlimited population growth has serious consequences in the near future e.g. severe shortage of energy and food. (b) Alternative farming systems are possible, but they require reducing the population by a factor 2, and thus the creation of jobs in a Hinterland. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
495.
We investigated the foraging habitats of the winter breeding community of tropical seabirds from Europa Island (Mozambique Channel) in September 2003. We focused our study on the dominant species of this austral community, the sooty tern (Sterna fuscata), the red-footed booby (Sula sula), and the frigatebirds, including the great (Fregata minor) and the lesser frigatebirds (F. ariel). We considered the at-sea distribution and abundance of these species in relation to chlorophyll concentration, sea-surface temperatures, sea-surface height anomalies, depth of the thermocline, distance to the colony, and presence of surface marine predators, flying fishes and other seabirds. Although the marine environment where seabirds foraged was oligotrophic, it presents the best feeding opportunities for seabirds for the area in winter. Our study demonstrates that the winter-breeding seabird species of Europa Island tend to forage in productive waters in association with other marine predators when possible. Sooty terns and frigatebirds were widely distributed in the whole study area, whereas red-footed boobies were not found farther than 160 km from their colonies and were associated with relatively productive waters. Sooty terns and red-footed boobies were aggregated where flying fishes were abundant. The presence of other marine predators was associated with larger multispecies feeding flocks than when no association occurred. Sooty terns, which are numerically dominant at Europa and adopted network foraging, seem to be catalysts of feeding events, and represented a good target for the other foraging species, especially frigatebirds. However, when possible, frigatebirds favour association with flocks of red-footed boobies.Communicated by S.A. Poulet, Roscoff  相似文献   
496.
The morphological expressions of imposex in gastropods have been classified into seven stages (S0–S6) with three types (a, b and c). This typical imposex scheme, however, fails to cover some new findings such as specimens with the proximal vas deferens section passing by the vaginal opening (VDSP) and aborted egg capsules. In the present study, Cantharus cecillei was sampled from the coastal waters of China from May to November in 2003. This species showed all the morphological expressions in the typical imposex scheme with the exception of S1b and S2b. In addition, specimens with VDSP occurred in all stages other than stage 4, and were documented for the first time with scanning electron micrographs or in histological sections. Besides VDSP, which was observed exteriorly, excrescent tissue, e.g. the vas deferens, also originated in the ventral channel or the inner wall of the pallial oviduct was extruded. Based on these new findings, the typical imposex scheme was modified to obtain one valid for C. cecillei. Types a*, b* and c* were added as new types corresponding to types a, b and c, respectively. S4* was also rearranged to correspond to S4; S4*, thus, no longer represented the end of imposex development. The updated scheme was not only valid for describing diverse expressions of imposex development in C. cecillei and Nassarius reticulatus, but could also be generalized to define various forms of VDSP in other species. Histological observation indicated that egg capsules would be blocked by the tissues of the vas deferens section or the extrusion of the pallial oviduct wall. This new mechanism, leading to the sterilization of imposex-affected females, was first conclusively revealed and described in the present scheme.Communicated by T. Ikeda, Hakodate  相似文献   
497.
This study investigated the possible roles of superoxide produced by raphidophyte and prymnesiophyte microalgae as an ichthyotoxic agent to damselfish and an allelopathic agent to bacteria. We found that the rate of superoxide production varied with algal cell density, with cell densities of the raphidophyte Chattonella marina >10,000 cells ml–1 producing less environmental levels of superoxide per cell (94±14 chemiluminescence units) than cell densities <10,000 cells=">–1 (390±54 units per cell). Microalgal cells have the capacity to change their superoxide production rate over a period of 1 h, dependent on cell density and metabolic activity. We also examined the effect of superoxide on suppression of bioluminescence of the marine bacterium Vibrio fischeri as a model for bacterial alleopathy and found that both superoxide and free fatty acids such as eicosapentaenoic acid (EPA; 20:53) present in raphidophyte microalgal cells cause suppression of bacterial bioluminescence. The combination of superoxide in the presence of EPA further enhanced bioluminescence suppression. Superoxide was also found to enhance the toxicity of free fatty acid EPA to damselfish (Acanthochromis polycanthus) at concentrations as low as 0.2 mg l–1. In conclusion, consideration should be given to density dependent and/or metabolic variations of toxicity when publishing minimum alert levels for superoxide producing ichthyotoxic microalgal species. A secondary role of superoxide production may be to enhance the toxicity of algal exudates or serve as an allelopathic agent against bacterial fouling.  相似文献   
498.
The analysis of genotypic shifts in field-exposed populations has been proposed as a tool for monitoring the environmental impacts of contaminants. Previous laboratory experiments showed the occurrence of genotypic shifts induced by copper exposure in samples of Hediste diversicolor from the Pialassa estuary (North Adriatic Sea, Italy). In order to test if genotype-tolerance responses observed were consistent at larger spatial scales, populations of H. diversicolor were sampled in three haphazardly chosen estuaries along the Italian coast (Comacchio, Pialassa, Serchio) and exposed to 0.48 mg l−1 Cu2+ under laboratory conditions. Survival analysis procedures were used to test for possible relationships between time-to-death and genotypes at three allozyme loci (ALD, FH, PGI). Genotype-tolerance responses observed at locus ALD were consistent among populations up to 2500 km distant, with genotype ALD 102/102 associated with the shortest survival times. Comparisons with previous laboratory experiments showed that responses to copper stress at locus ALD were also consistent in time, with genotypes ALD 102/102 and ALD 100/102 associated with higher 96 h mortality ratios. Results suggested the occurrence of stable relationships between genotypes at locus ALD and tolerance responses of H. diversicolor to copper stress. Conversely, genotype-tolerance responses at loci PGI and FH were not consistent either in space (among populations from the three estuaries) or in time (between laboratory experiments), being possibly affected by site-specific features of populations or stochastic factors. Results show that genotype-tolerance responses should be carefully verified at different spatial and temporal scales, before considering genotypic shifts among the possible tools for monitoring the effects of environmental stressors.  相似文献   
499.
The concept of participation in rural development has been evolutionary for the past two decades with those involved, such as development agencies and governments, particularly in rural water supply, re-evaluating their active role. The move towards effective community participation has encouraged a shift from the traditional top-down to a bottom-up approach whereby there is a decentralisation of unevenly distributed resources and power to empower a community and allow mobility of ‘people participation’. The Molinos water project is the first large-scale development project of its kind introduced into the village of Molinos in an under-developed area of Chile, where there has been no tradition of people participation. The project objective was to implement a low technology, low budget water treatment plant to the village of Molinos. Various aspects have hindered the continued development of the project including both technical and financial. In terms of people participation, the initial approach used was the top-down approach. There was a failure to fully integrate the community or inform the community in a formal manner about the project and consult them regarding key project issues. This case study illustrates that the lack of comprehensive consultation and the low level of participation of the community on the participatory scale does not achieve much in terms of people-centred benefits. For governance at the local level to be effective, participation should be inclusive and communicative so as to enhance transparency throughout the project lifetime. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
500.
This paper deals with the various factors that condition underdevelopment in the world. It suggests some alternatives and points out the potential opportunities that both the developed and the underdeveloped world will have in the coming years to change the gloomy prospects that we see today. The present paper outlines the trends in historical priorities in development, changing as they pass from economic development to social development to ecological conservation – the three pillars of Sustainable Development.The paper analyses the importance of geography, a very relevant and often neglected conditioning factor. Also, it analyses the role of socio-economic conditioning factors like political immaturity, demographics, land ownership and external debt.Furthermore, the current opportunities for economic take-off are presented, from cash surpluses to low interest rates, from natural resource management to tourism or migration, from the Information Revolution to liberalisation of agricultural markets. Current obstacles are also analysed. The paper, on the basis of current facts and figures, reaches the conclusion that there is a structural need for sustained development aid for most poor countries, but it must be distributed in a more rational way.Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
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