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211.
FILIPPO BUSSOTTI ENRICO CENNI ALBERTO COZZI MARCO FERRETTI 《Environmental monitoring and assessment》1997,45(2):181-194
A survey of the crown status of Turkey oak Quercus cerris L.) trees in the boron-rich area atTravale (Southern Tuscany, Italy) was carried outin order to evaluate the impact ofgeothermal power plants. Crown thinness was assessed andmorphological and chemical tests werecarried out on leaf samples. Leaf area and dry weight weredetermined as morphological parameters;while the chemical measurements performed included nitrogenand potassium (among the nutrients),and sulphur, boron, arsenic and mercury (among the elements ofgeothermal origin). Acute damagewas found only in the area immediately adjacent to the outletsand is the result of the action of boron;crown thinness, on the other hand, is affected by the natureof the geological substrate. High quantitiesof sulphur were found in leaves throughout the survey area,due both to the availability of this elementin the geopedological substrate and to the atmospheric inputof geothermal H2S. The leafcontent of this element correlates negatively with thedistance from the power plants. Boron andarsenic are the other geothermal origin elements most commonlyfound in plant matrices. The presenceof these two elements is associated with leaf area reductionand/or an increase of specific dry weight.The most significant impact on the environment appears to beexerted by the southernmost powerplant, where there is an unfavourable ratio between quantityof emissions and height of the chimneys. 相似文献
212.
213.
Assessing Ecological Integrity of Ozark Rivers to Determine Suitability for Protective Status 总被引:3,自引:0,他引:3
Preservation of extraordinary natural resources, protection of water quality, and restoration of impaired waters require a strategy to identify and protect least-disturbed streams and rivers. We applied two objective, quantitative methods to determine stream ecological integrity of headwater reaches of 10 Ozark rivers, 5 with Wild and Scenic River federal protective status. Thirty-four variables representing macroinvertebrate and fish assemblage characteristics, in-stream habitat, riparian vegetation, water quality, and watershed attributes were quantified for each river and analyzed using two multivariate approaches. The first approach, cluster and discriminant analyses, identified two groups of river with only one variable (% forested watershed) reliably distinguishing groups. Our second approach employed ordinal scaling to compare variables for each river to conceptually ideal conditions that were developed as a composite of optimal attributes among the 10 rivers. The composite distance of each river from ideal was then calculated using a unidimensional ranking technique. Two rivers without Wild and Scenic River designation ranked highest relative to ideal (highest ecological integrity), and two others, also without designation, ranked most distant from ideal (lowest ecological integrity). Fish density, number of intolerant fish species, and invertebrate density were influential biotic variables for scaling. Contributing physical variables included riparian forest cover, water nitrate concentration, water turbidity, percentage of forested watershed, percentage of private land ownership, and road density. These methods provide a framework for refinement and application in other regions to facilitate the process of establishing least-disturbed reference conditions and identifying rivers for protection and restoration. 相似文献
214.
Xin-Rui Li Hiroshi Koseki 《Journal of Loss Prevention in the Process Industries》2005,18(4-6):455-459
In this paper, compared with a UN cylindrical 500 mL Dewar (H.4 in the UN tests), a spherical 1 L Dewar vessel was used to study the early stages of runaway reactions of several liquid and solid samples, including three organic peroxides and a reactive material. The samples were filled in the vessels and the temperature profiles versus times at different positions of the samples were measured. As a result, the minimum temperatures, defined as the SADT, were averagely 10 K lower than those measured in the cylindrical Dewar vessels. At the same time, the temperature profiles of solids in the spherical Dewars tended to be homogeneous. The heat transfer coefficient of a spherical Dewar is only 0.18 W/K/m, one-eighth of a conventional cylindrical Dewar vessel. Meanwhile it has a low phi factor. These factors are essential to simulate low heat loss bulk conditions in the equilibrium process and at the early stage of a runaway reaction. To characterize the ability of the adiabaticity of a storage vessel, it can be seen that a spherical Dewar could simulate the plant process having critical storage size of a reactive-material, r0, approximately 0.6 m. It is recommended that such a technique is used to investigate the SADT of an unstable material in larger scale packaging or a material with very weak heat release in industry. 相似文献
215.
西南地区旅游资源丰富多样,但经济发展水平相对落后.要实现西南地区经济社会的腾飞,必须实施生态文化旅游科技发展战略.在分析西南地区旅游资源特点的基础上,指出了旅游发展的战略目标及主要任务,并提出了相关建议. 相似文献
216.
Füreder L. Vacha C. Amprosi K. Bühler S. Hansen C. M. E. Moritz C. 《Water, Air, & Soil Pollution: Focus》2002,2(2):275-294
Natural and near-natural streams are rare in the densely populated areas of the Alps. A variety of anthropogenic impacts have resulted in the alteration and sometimes even complete destruction of these systems. Nowadays it is difficult to find un-impacted streams that are strongly needed to define the natural variability and ecosystem processes. The results from freshwater inventories and habitat assessments conducted in protected areas in Austria (Nationalpark Hohe Tauern) and Italy (Naturpark Rieserferner-Ahrn) were used to develop a comprehensive typology of Alpine streams. Three different levels were used to discriminate between the distinct stream/river types: source (glacial vs. non-glacial), hierarchy (i.e. location within the stream system) and topography/ channel morphology. Important characters defining the structure and function of these stream types are gradient, substrate composition, flow pattern and riparian vegetation. Benthic fauna assemblages from 99 near-natural stream segments in glacial and non-glacial systems demonstrated the effect of glaciation on abundance levels of the total macroinvertebrate fauna, EPT taxa (Ephemeroptera, Plecoptera and Trichoptera) and the chironomid subfamily Diamesinae in different altitudes. A general decrease of abundances with increasing altitude was found. While stream segments with a degree of glaciation >10% primarily showed reduced abundances at all altitudes, lower (<10%) or no glaciation did not influence invertebrate abundances at lower reaches. Due to the near-natural conditions of the selected stream segments, a valuable definition of reference conditions of Alpine streams based on habitat characteristics is available. As a basis it offers excellent opportunities to conduct holistic interdisciplinary studies in protected areas in the future. 相似文献
217.
James G. Thompson Robert Reynolds 《Journal of the American Water Resources Association》2002,38(6):1661-1667
ABSTRACT: This article reports the findings of a case study of a major California water management district's effort to change its management approach. The following key findings and factors have influenced the Salinas basin management plan (BMP) and its progress: (1) the Salinas Valley is an economy dominated by highly sophisticated irrigated agriculture dependent on ground water; (2) a persistent pattern of agricultural overdraft of ground water has hurt growers primarily in the north end of the valley via induced saline intrusion of irrigation wells; (3) a complex set of water institutions, property and water rights, and land lease practices offer little incentive for good stewardship of land and water; and (4) the BMP approach initially may have intensified tension among growers and between growers and other water user groups. Water rules and practices in the Salinas Valley and Monterey County have evolved through a long historical process of adaptations. Therefore, any significant changes in local water use practices need to be understood in terms of cultural change, that is, changes in deeply held values, beliefs, and assumptions. We believe the BMP and the MCWRA are succeeding when evaluated from this evolutionary perspective. The fact that both still exist relatively intact testifies that they are working, albeit slowly. 相似文献
218.
G.O. Anoliefo O.S. Isikhuemhen N.R. Ochije 《Journal of Agricultural and Environmental Ethics》2003,16(3):281-296
Cultural taboos and their sanctionshave helped to check abuse of the environmentat least among the local people. The disregardfor these traditional checks and balancesespecially among Christians has adverselyaffected their enforcement at this time. Theenvironment and culture preservation inAwka-South were investigated. The faithfulobservance of the traditional laws in the studyarea was attributed to the fact that Awka-Southarea had remained occupied by the same peoplefor centuries. The study showed that thepreserved forests and their shrines in Nibotown have largely remained intact. In Nisetown, however, with nine shrines still inexistence, the rules have relaxed a little,mainly because they embraced modernization. Inthis town, the fringes of the forests may beused for farming but no felling of trees wouldbe allowed. The ``god' of the shrine in Obunaguvillage was much revered until the advent ofChristianity. This religion has had an erodingeffect on the taboos, which were put in placeto protect their forests and streams. Theabandonment of traditional cultural practicesis doing harm that goes beyond the abrogationof traditional cultural practices to seriousthreat to natural environmental structures. Thecultures of the different tribes in Nigerianeed to be revisited for evaluation and studiesto enable their integration into modernpractices that will make the environment moresustainable. This will be more productive thanthe unilateral introduction of programs,execution, and maintenance methods that arecompletely new, or in many cases run contraryto the cultural practices of the local peopleand tribes of Nigeria. 相似文献
219.
Environmental issues are increasingly discussed in Egypt, and there is some progress in dealing with pollution. This paper examines the environmental understandings of Egyptians living in four localities. People are preoccupied with such pollution problems as dirty streets, dirty air and water, and noise, for they aspire to live in a clean, healthy environment. To achieve this, they pressure the government, and take certain individual and collective actions themselves, although direct political action is rare. 相似文献
220.
Lotte Holm 《Journal of Agricultural and Environmental Ethics》2003,16(6):531-544
Functional foods are a challenge tofood health policies, since they questioncentral ideas in the way that food healthpolicies have been developed over the lastdecades. Driven by market actors instead ofpublic authorities and focusing on the role ofsingle foods and single constituents in foodsfor health, they contrast traditional wisdombehind nutrition policies that emphasize therole of the diet as a whole for health.Sociological literature about food in everydaylife shows that technical rationality co-existswith other food related rationalities, such aspractical and economic rationalities, socialand relational rationalities, and symbolicrationalities that influence citizens' ordinaryeating habits. An examination of lay views onexpert knowledge about food and health showthat skepticism exists with respect to thebasis of and balance of expert advice. Critical points with respect to how functionalfoods may influence routines in the populationswith relevance for public health include thefact, that they promote a way of thinking offood and health that is in conflict withwell-established practical ways of ensuring abalanced diet. 相似文献