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301.
Zohra Belala Mejdi Jeguirim Meriem Belhachemi Fatima Addoun Gwena?lle Trouv�� 《Environmental Chemistry Letters》2011,9(1):65-69
The removal of toxic metals from wastewaters by biosorption, based on the metal-binding capacities of various biological materials,
has received much interest. However, the success of this approach depends on economic feasibility, which can be obtained by
optimization of the environmental conditions. This paper evaluates, for the first time, the use of low-cost biosorbent (date
stones (DS) and palm-tree waste (PTW)) to eliminate Cu(II) from aqueous solutions. The effect of some parameters on copper
biosorption has been studied using date stones and palm-tree waste as solid sorbents. Results show that the highest percentage
of copper adsorption was obtained for the smallest size of the sorbent particles. The biosorption process was found to occur
rapidly, i.e. the maximum sorption capacity was reached within 20 min. The process involved pseudo-second-order kinetics with
an activation energy value within the normal range considered for processes, where a physical interaction between the sorbate
and the sorbent solid predominated. The thermodynamic parameters of the copper ions uptake onto the solid sorbents indicated
that, the process was endothermic and proceeds spontaneously from the date stones. However, the thermodynamic studies of the
adsorption of copper on palm-tree waste indicated that the process was exothermic and proceeds spontaneously. 相似文献
302.
Community Sustainability Plans to enable change towards sustainable practice – a Scottish case study
Joanneke Hélène Joséphine Kruijsen Alan Owen Donald Murray Gordon Boyd 《Local Environment》2013,18(7):748-766
There is a need for a global shift towards a low-carbon society and this requires action at the local level. The aim of the study into sustainable community development is to clarify the role of a community as a whole rather than the role of individuals within that community. Mixed methods of literature review and empirical study have been used to translate the knowledge and experience with urban sustainable development into empirical knowledge of a rural, market town setting. The exemplary case study is the Scottish market town Huntly. The main findings of the study show the need for three ingredients for a Community Sustainability Plan for a town such as Huntly. Community involvement is crucial in developing such plans in a rural setting. Further research in more remote settings, e.g. coastal and island communities, is needed to allow broader conclusions on rural sustainable development. 相似文献
303.
Laurence Michel-Calemard Gaëtan Lesca Yves Morel Dominique Boggio Henri Plauchu Jocelyne Attia-Sobol 《黑龙江环境通报》2004,24(7):519-523
This is the first report of a fetus affected with campomelic acampomelic dysplasia presenting with increased nuchal translucency. Ultrasonography at 13 weeks of amenorrhea showed a nuchal translucency 5.6 mm thick. The karyotype performed on amniotic fluid cells was normal (46,XY). Ultrasonography at 22 weeks revealed a normal femoral length and female genitalia. A second amniocentesis was performed to confirm the karyotype and for dosage of steroid hormones. Testosterone dosage was low, corresponding to a female fetus. Ultrasonography at 32 weeks showed growth retardation of the long bones (<3rd centile) that were not curved. A severe malformation syndrome was suspected and the pregnancy was terminated at 33 weeks. The fetus displayed macrocephaly, facial dysmorphism and female external genitalia. X ray showed straight and thickened long bones, hypoplastic scapulae and moderate platyspondyly. In view of the association of sex reversal, hypoplasia of the scapulae, and the presence of straight long bones, campomelic acampomelic dysplasia was suspected and confirmed by the finding of a SOX9 mutation. This case shows the importance of a careful echographic survey in a fetus with a nuchal translucency > 4 mm, especially if there is discordance between phenotypic and genotypic sex, since growth retardation may occur later during the pregnancy. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
304.
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306.
Ryan Plummer Jonas Velaniškis Danuta de Grosbois Reid D. Kreutzwiser Rob de Loë 《Environmental Science & Policy》2010,13(6):535-548
While new environmental policies and procedures often are developed incrementally, they can also result from crises or other significant events. In situations where policies and procedures are introduced in response to a crisis, questions about the strengths and weaknesses of existing mechanisms, and the extent to which they can be used to address concerns, may be ignored. This paper explores the complexities of introducing new policies and processes where planning systems and procedures already exist. Drinking water source protection policies that are being developed in response to the tragic events in Walkerton, Ontario, Canada serve as the context for the inquiry. Three case study watersheds were selected to reflect the diversity of municipal jurisdictions and water supply systems in Ontario. A content analysis was undertaken on regulatory and non-regulatory policy documents to determine the extent to which they addressed elements of the multi-barrier approach for drinking water safety. Findings from the research reveal considerable evidence of the multi-barrier approach in the policy and guiding documents analyzed. Policy development in response to a crisis can advance progress on the issue of drinking water safety and coincide with emerging governance strategies. Policy effectiveness may be enhanced by considering existing policies as well as contextual and jurisdictional differences. 相似文献
307.
Pablo del Río Javier Carrillo-Hermosilla Totti Könnölä Carlos García Suárez 《Mitigation and Adaptation Strategies for Global Change》2008,13(8):863-885
This paper empirically shows how the uncertainty associated to the absence of a mitigation regime which follows the United
Nations Framework Convention on Climate Change Kyoto Protocol (UN FCCC Kyoto Protocol) is affecting investments in abatement
activities in the EU electricity sector and, thus, future emissions levels. Based on a survey of EU electric utilities, it
identifies the most likely post-Kyoto scenarios considered by them and how they are coping with such uncertainty in their
investment decisions. It is found that firms react differently to such uncertainty and adopt different strategies to cope
with it, diversifying their emissions control activities. Although most companies foresee post-Kyoto compliance regimes with
emissions trading systems, they differ in their perceptions of the form that a post-Kyoto regime could take and are, thus,
positioning differently to face such regime. The particular features of each company and the country where they operate affect
their perception of the uncertainties, their position regarding a possible post-Kyoto regime and their inclination to carry
out mitigation activities. Complying with Kyoto (and, eventually, post-Kyoto) targets significantly influences the investment
decisions of European electricity companies. Uncertainty about a post-Kyoto regime may already be affecting investments in
mitigation activities in the electricity sector. Therefore, significant progress has to be made in the definition of a post-Kyoto
regime. It is urgent to define and agree internationally the emissions reduction objectives and the mitigation instruments
that will be accepted for compliance, ensuring continuity of the international emissions trading system foreseen in the Kyoto
Protocol.
相似文献
Pablo del RíoEmail: |
308.
Alain Dejean Céline Leroy Bruno Corbara Régis Céréghino Olivier Roux Bruno Hérault Vivien Rossi Roberto J. Guerrero Jacques H. C. Delabie Jérôme Orivel Raphaël Boulay 《Die Naturwissenschaften》2010,97(10):925-934
Myrmecophytes offer plant-ants a nesting place in exchange for protection from their enemies, particularly defoliators. These obligate ant–plant mutualisms are common model systems for studying factors that allow horizontally transmitted mutualisms to persist since parasites of ant–myrmecophyte mutualisms exploit the rewards provided by host plants whilst providing no protection in return. In pioneer formations in French Guiana, Azteca alfari and Azteca ovaticeps are known to be mutualists of myrmecophytic Cecropia (Cecropia ants). Here, we show that Azteca andreae, whose colonies build carton nests on myrmecophytic Cecropia, is not a parasite of Azteca–Cecropia mutualisms nor is it a temporary social parasite of A. alfari; it is, however, a temporary social parasite of A. ovaticeps. Contrarily to the two mutualistic Azteca species that are only occasional predators feeding mostly on hemipteran honeydew and food bodies provided by the host trees, A. andreae workers, which also attend hemipterans, do not exploit the food bodies. Rather, they employ an effective hunting technique where the leaf margins are fringed with ambushing workers, waiting for insects to alight. As a result, the host trees’ fitness is not affected as A. andreae colonies protect their foliage better than do mutualistic Azteca species resulting in greater fruit production. Yet, contrarily to mutualistic Azteca, when host tree development does not keep pace with colony growth, A. andreae workers forage on surrounding plants; the colonies can even move to a non-Cecropia tree. 相似文献
309.
The Great American Biotic Interchange has been the predominant paradigm for explaining biotic diversification in the Nearctic/Neotropical
overlap or Mexican Transition Zone, which is commonly explained by the collision of the North and South American continental
plates, which began in the Oligocene and fused both landmasses. In the most far-reaching cladistic biogeographical analysis
of the area to date, evidence has been found supporting the existence of a remnant Caribbean region extending from eastern
Mexico to southeastern USA, a hypothesis that challenges current views of the Great American Biotic Interchange and the Mexican
Transition Zone. We show herein that an older terrane, which has drifted to the present day positions of Yucatan and Cuba,
may be biogeographically linked to an early ‘Gondwanan’ biota of the Paleocene (ca. 60 Ma). The evidence indicates an east–west
biotic divide in Mexico, existing before the collision and formation of Central America. The south–north division of the country,
previously recognized by several authors as associated with the Great American Biotic Interchange and the Mexican Transition
Zone, is of a younger age.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
310.
Giovannangelo ME Gehring U Nordling E Oldenwening M van Rijswijk K de Wind S Hoek G Heinrich J Bellander T Brunekreef B 《Environment international》2007,33(1):9-16
BACKGROUND: Mold growth is believed to be one causative factor underlying the association between dampness in buildings and increased respiratory morbidity. Measurements of beta(1-->3)-glucans and fungal extracellular polysaccharides (EPS) are used as markers of mold exposure in field studies. Little is known about their levels and determinants in homes. OBJECTIVE: To study levels and determinants of beta(1-->3)-glucan and EPS levels in mattress and living room floor dust in three European countries. METHODS: Mattress and living room floor dust was collected in the homes of 1065 German, Dutch, and Swedish (pre-)school children. All samples were analyzed for beta(1-->3)-glucans and EPS in one central laboratory. Determinants were assessed by questionnaire. RESULTS: Amounts of dust, EPS and beta(1-->3)-glucan levels differed between countries. Amounts of dust, beta(1-->3)-glucan and EPS levels for mattresses were only weakly correlated with those for living room floors. Floor dust beta(1-->3)-glucan loads, EPS loads and EPS concentrations were strongly correlated with the amount of dust sampled, which is largely determined by the type of floor that was sampled (carpeted floors had 5-20 higher amounts of dust). None of the other determinants was consistently and statistically significantly associated with amounts of dust, beta(1-->3)-glucan and EPS concentrations on floors and mattresses. CONCLUSION: Mattress dust and floor dust are two different measures of exposure to the investigated mold components. Living room floor beta(1-->3)-glucan and EPS loads and EPS concentrations are largely determined by the type of floor sampled. Differences between countries can only partly be explained by the determinants studied. 相似文献