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741.
To assess the conservation status of the world's land mammals, we compiled data on the number of total species, endemic species, recently extinct species, and currently endangered species for 155 countries. Total species richness was significantly correlated with territorial land area, whereas number of endemic species was only weakly correlated with both area and total number of species. The large amount of variation left unexplained by species-area regressions reflects the influence of other factors, such as latitude, topographic and habitat heterogeneity, and historical biogeography, on species richness and especially on patterns of endemism. Countries of particular conservation concern, because they have rich mammalian faunas containing many endemic species, are the large islands of Australia, Madagascar, Indonesia, and the Philippines, as well as continental Mexico. Patterns of recent extinctions and the current endangered status of species were difficult to interpret, largely because of inadequate and inconsistent data. The majority of officially listed endangered species are large, well known, and popular mammals, such as primates, ungulates, and carnivores, whereas the majority of species known to have gone recently extinct and likely to be currently threatened are small and inconspicuous, such as rodents and bats. Our work not only illustrates the role of ecological, evolutionary, and biogeographic processes in the origin and maintenance of land mammal diversity, it also presents the information at the level of biogeographic regions and political units where management and policy must be applied in order to slow the loss of this diversity. 相似文献
742.
Variable availability of the purified dihydrochloride salt of 3,3'-dimethoxybenzidine (DMB; ortho-dianisidine) led us to investigate the effects of reagent purity on the analytical results obtained when this reagent is used in the photometric determination of the disinfection byproduct bromate. After analyte ions are separated by ion chromatography, a solution of DMB (post-column reagent) is added to the eluate and the DMB is oxidized, thereby producing a chromophore detected by its absorbance. Although some commercial products of undefined grade performed well, others did not. Variability was also observed between lots of purified material. Sensitivity at low concentrations (< 5 micrograms L-1 BrO3-) varied by a factor of up to 10. In some cases, the lower limit of detection for photometric detection was greater than that obtained using conductivity detection, as high as 5-7 micrograms L-1 BrO3-. An impurity or several impurities are suspected to be responsible for deviations from linearity at low analyte concentrations. This investigation underscores the need for ensuring reagent purity in environmental analyses. Ideally, chemical manufacturers will meet the needs of analytical chemists who test potable water and begin producing a high grade material in sufficient quantities to meet monitoring requirements. The establishment of third-party standards for a spectrophotometric grade of DMB.2HCl would be helpful in ensuring that a variety of manufacturers could supply products of uniformly high quality that would be suitable for the measurement of bromate in public drinking water supplies. 相似文献
743.
Thomas C. Brown Martin M. Fogel 《Journal of the American Water Resources Association》1987,23(6):1149-1160
ABSTRACT: Although the effects of vegetation management on streamflow have been studied in many locations, the effects of augmented streamflow on downstream water users have not been carefully analyzed. This study examines the routing of streamflow increases that could be produced in the Verde River Basin of Arizona. Reservoir management and water routing to users in the Salt River Valley around Phoenix were carefully modeled. Simulation of water routing with and without vegetation modification indicates that, under current institutional conditions, less than one-half of the streamflow increase would reach consumptive users as surface water. Most of the remainder would accumulate in storage until a year of unusually heavy runoff, when it would add to reservoir spills. Under alternative scenarios, from 39 to 58 percent of the streamflow increase was delivered to consumptive users. 相似文献
744.
Curtis A. Brown 《Journal of the American Water Resources Association》1984,20(3):331-337
This paper describes the successful application of a multiobjective planning framework, incorporating substantial public involvement, to a major water resources decision involving intense confilcts. The study was initiated to help resolve more than a decade of controversy over a project proposed to control flooding and provide regulatory storage in the Phoenix, Arizona, area. The public was actively involved in the development of study goals and the specification of acceptable tradeoffs between multiple objectives. A wide range of structural and nonstructural alternatives was formulated and evaluated in relation to these objectives, and broad-based support was developed for a new plan. Reasons for the successful outcome are discussed, as well as implications for water resources planning under the new Federal Principles and Guidelines. 相似文献
745.
746.
Catherine Brown 《Disasters》1999,23(3):234-256
Protracted conflict and violence in Burma have been conducive to the growth of the opium industry, Burma's single financial success in recent years of economic crisis and authoritarian rule. This in turn has fed violence and subsequent humanitarian crisis. This paper argues that the underlying political economy of the conflict has been overlooked, while conflict itself has been treated as a peripheral factor in questions of 'development', and further that the opium dynamic is a vital factor in continued violence and vulnerability for non-combatants in the region. A political economy approach, identifying the beneficiaries of violence, will offer a more holistic and effective approach to the protracted crisis. 相似文献
747.
Institutions play an important role in the adaptive capacity of a system in responding to climate change. This review paper
characterizes the status of the collective institutional response (government, industry, First Nation, community, civil society)
to climate change in the forest sector of the Canadian province of Ontario, and highlights the presence and nature of inter-institutional
networks as part of the response. Based on a synthesis of the commonalities in the public administration and policy literature
on tackling wicked problems, and the resilience literature, inter-institutional networks, which foster exchange of different
types of knowledge, are an important aspect of enhancing the adaptive capacity of social–ecological systems such as the forest
sector. Based on a content analysis of publicly available documents and insights gained from representatives of government,
community members and non-governmental organizations, mitigation and adaptations strategies are described. At the provincial
level there have been some new innovations in inter-institutional networks, but expansion of the forest stakeholders involved
in such networks would further enhance adaptive capacity. In particular, it is important to network with First Nations and
other forest-dependent communities who have a heightened vulnerability to climate change. The presence of a collaborative
capacity builder could foster the transfer, receipt and integration of knowledge across the networks, and ultimately build
long-term collaborative problem-solving capacity in the Ontario forest sector.
相似文献
H. Carolyn Peach BrownEmail: |
748.
Korobova EM Brown JB Ukraintseva NG Surkov VV 《Journal of environmental radioactivity》2007,96(1-3):144-156
Plant species, forming important components of Arctic food chains and of interest from a monitoring perspective, were studied at 36 plots representing flood plain and terrace landscapes of the Yenisey River and Estuary from its upper delta to the gulf. (137)Cs contamination densities at the plots varied from 0.35kBq/m(2) (central delta, sandy riverside plot) to 88kBq/m(2) (the upper delta plot) indicating both global and regional sources of anthropogenic pollution. Cs-137 levels in plants were within the range expected from global fallout inputs and varied from 31 to 140Bq/kg d.w. increasing in dominant groups in the order: grasses相似文献
749.
Hosseini A. Brown J. E. Avila R. Beresford N. A. Oughton D. 《Environmental Modeling and Assessment》2022,27(2):311-326
Environmental Modeling & Assessment - In Europe, the two main nuclear accident response decision support systems in use are ARGOS and JRODOS, both of which make use of the FDMT (Food Chain and... 相似文献