全文获取类型
收费全文 | 22709篇 |
免费 | 86篇 |
国内免费 | 116篇 |
专业分类
安全科学 | 292篇 |
废物处理 | 1352篇 |
环保管理 | 2771篇 |
综合类 | 3482篇 |
基础理论 | 6086篇 |
环境理论 | 5篇 |
污染及防治 | 5055篇 |
评价与监测 | 1769篇 |
社会与环境 | 2039篇 |
灾害及防治 | 60篇 |
出版年
2022年 | 246篇 |
2021年 | 240篇 |
2020年 | 101篇 |
2019年 | 116篇 |
2018年 | 1721篇 |
2017年 | 1616篇 |
2016年 | 1476篇 |
2015年 | 321篇 |
2014年 | 292篇 |
2013年 | 862篇 |
2012年 | 805篇 |
2011年 | 1868篇 |
2010年 | 1160篇 |
2009年 | 1086篇 |
2008年 | 1452篇 |
2007年 | 1881篇 |
2006年 | 437篇 |
2005年 | 451篇 |
2004年 | 414篇 |
2003年 | 514篇 |
2002年 | 511篇 |
2001年 | 446篇 |
2000年 | 329篇 |
1999年 | 213篇 |
1998年 | 141篇 |
1997年 | 123篇 |
1996年 | 108篇 |
1995年 | 154篇 |
1994年 | 149篇 |
1993年 | 123篇 |
1992年 | 131篇 |
1991年 | 150篇 |
1990年 | 120篇 |
1989年 | 129篇 |
1988年 | 132篇 |
1987年 | 114篇 |
1986年 | 83篇 |
1985年 | 100篇 |
1984年 | 142篇 |
1983年 | 134篇 |
1982年 | 125篇 |
1981年 | 97篇 |
1980年 | 95篇 |
1979年 | 107篇 |
1978年 | 89篇 |
1977年 | 84篇 |
1976年 | 78篇 |
1975年 | 90篇 |
1974年 | 102篇 |
1965年 | 74篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
An Exploration of the Value of Naturalness and Wild Nature 总被引:2,自引:0,他引:2
Ben Ridder 《Journal of Agricultural and Environmental Ethics》2007,20(2):195-213
The source of the value of naturalness is of considerable relevance for the conservation movement, to philosophers, and to
society generally. However, naturalness is a complex quality and resists straightforward definition. Here, two interpretations
of what is “natural” are explored. One of these assesses the naturalness of species and ecosystems with reference to a benchmark
date, such as the advent of industrialization. The value of naturalness in this case largely reflects prioritization of the
value of biodiversity. However, the foundation of our understanding of naturalness is that it describes processes that are
free of human intervention. Conflict between the two interpretations of naturalness is apparent in the claim that naturalness
can be enhanced by human intervention, in the form of ecological restoration. Although naturalness in its purest form precludes
human intervention, some human activities are also apparently more natural than others. This continuum of naturalness relates
to the autonomy of the individual from abstract instrumentalism, which describes a particular form of influence ubiquitous
in contemporary society. The value of naturalness reflects both dissatisfaction with these threats to personal autonomy, and
respect for wild nature as the embodiment of a larger-than-human realm. 相似文献
942.
Başak K. Taşeli 《The Environmentalist》2007,27(3):315-327
Environmental pollution and degradation of ecosystems considerably affect the natural resources. The Turkish Government is
aware of the importance of the preservation of natural ecology and thereby the environmental conservation of many species
in their natural habitat. This paper provides critical assessments of the problems and possible solutions in the identification,
implementation and management of the Specially Protected Areas (SPAs) system by giving basic information about stakeholders
and their responsibilities that currently offer nature conservation in Turkey. The goals of the article are to analyze how
the SPAs interface with the local people, especially the villagers who have dwelt there before SPA designation and how people-SPA
conflicts resolved; to show how effective the SPA conservation objectives have been; to outline the significance of informing
and empowering people in nature conservation for the protected area management and to show the importance of planning at all
levels during protection of the natural, archeological and cultural values of the SPAs. 相似文献
943.
Ben A. Minteer Elizabeth A. Corley 《Journal of Agricultural and Environmental Ethics》2007,20(4):307-333
Few disputes in the annals of US environmentalism enjoy the pedigree of the conservation-preservation debate. Yet, although
many scholars have written extensively on the meaning and history of conservation and preservation in American environmental
thought and practice, the resonance of these concepts outside the academic literature has not been sufficiently examined.
Given the significance of the ideals of conservation and preservation in the justification of environmental policy and management,
however, we believe that a more detailed analysis of the real-world use and understanding of these ideas is needed. In this
paper, we describe the results of a qualitative, semantic study of the concepts of conservation and preservation undertaken
in the context of the Chattahoochee National Forest (CNF), located in northern Georgia (USA). Thirty in-depth interviews were
conducted with scientists and north Georgia residents either interested or involved in the future management of the forest.
Respondents were asked to define conservation and preservation in their own words and to indicate which approach they felt
was more appropriate for the management of the CNF. Qualitative content analysis was used to elicit a set of recurring themes
for each foundational concept. Taken together, these themes help to flesh out the meaning of conservation and preservation
for citizens and scientists today, and illustrate the evolving nature of two of the more significant and venerable ideas animating
US environmental policy and management. 相似文献
944.
The microbiological and physico-chemical characteristics of the drinking water supplied by the Central Borehole at the University
of Benin, Ugbowo Campus were investigated. The investigation entailed assessment of the pH, turbidity, total suspended solids,
total dissolved solids, dissolved oxygen, temperature, salinity, conductivity, nitrate, nitrite, phosphate, sulphate, chloride,
N-nitroso compounds, cadmium, chromium, nickel, lead, zinc, manganese, iron, coliform count, BOD5 and COD of the water at the Central Borehole and at ten residential quarters. The assessment indicated that the water was
fit for drinking and other domestic applications. Results were also compared with WHO, EU and Nigeria FEPA standards. The
results showed that the pH values of the water (5.01–5.86) and total coliform count (1–2/100 ml) expressed as MPN were outside
the limits set by the WHO, EU and FEPA. The data also showed that the other water quality parameters assessed were within
WHO, EU and FEPA permissible limits. The results of ANOVA showed that significant changes occurred during distribution. 相似文献
945.
The optimized BCR sequential extraction procedure (proposed by the Standards, Measurements and Testing Programme (SM&T) of
the European Union) was applied to seven topsoil samples from refuse dump sites for the determination of Cu, Zn, Ni, Pb and
Cd. The metals were partitioned into four operationally defined chemical fractions: acid extractable, reducible, oxidizable
and residual, and analysed using flame atomic absorption spectrophotometry, FAAS.
The results were compared with total metal concentrations obtained using HNO3, HClO4 and HF digestion procedures. Results for total metal analysis ranged from - 15.55 to 43.45 for Cu, 37.15 to 222.35 for Zn,
5.15 to 12.10 for Ni, 10.30 to 93.05 for Pb and 0.35 to 3.75 for Cd in μgg−1 dry weight. The results of the partitioning study showed that zinc prevailed in the more soluble fractions and was distributed
between the acid-extractable (32.4%) and the reducible (40.3%) fractions, whereas Pb was distributed mainly in the reducible
fraction. Copper and nickel were predominantly associated with the reducible and residual fractions - 53.4, 33.3 and 51.1,
24.1% respectively. The ranking of the four fractions for the partitioning of cadmium was: reducible > residual > oxidizable
> acid extractable. The percentage recovery for all metals when comparing total metal concentration with the fractional sum
of the optimized BCR procedure, were of the order: Zn(93%) > Pb(83%) > Cu(78) > Cd > (68%) > Ni(63%). 相似文献
946.
Marko S. Markov 《The Environmentalist》2007,27(4):465-475
Magnetic and electromagnetic fields are now recognized by the 21st century medicine as real physical entities that promise
the healing of various health problems, even when conventional medicine has failed. Today magnetotherapy provides a non-invasive,
safe, and easy method to directly treat the site of injury, the source of pain and inflammation, and other types of diseases
and pathologies. Millions of people worldwide have received help in treatment of musculoskeletal system, as well as pain relief.
Pulsed electromagnetic fields are one important modality in magnetotherapy and recent technological innovations, such as Curatron
pulsed electromagnetic field devices, offer excellent, state of the art computer controlled therapy system. In this article
the development, state of the art and future of pulsed electromagnetic field therapy are discussed. 相似文献
947.
Ellen-Marie Forsberg 《Journal of Agricultural and Environmental Ethics》2007,20(5):455-468
The ethical matrix approach was developed by Prof Ben Mepham and his colleagues at the University of Nottingham in the early
1990s. Since then the approach has received increasing attention and has been used by several researchers in different projects
related to assessing ethical impacts of different food production technologies and other policy options of societal concern.
The ethical matrix is sometimes understood simply as a checklist of ethical concerns, but might also be seen as a guide to
coming to conclusions on moral questions. The problem I discuss in this paper relates to how using the ethical matrix method
as a decision guide can be combined with respecting pluralism. The aim of the paper is to suggest a framework making it possible
to – at the same time – enhance public justification of judgments and respect pluralism. I argue that pluralism is fundamental
to the ethical matrix approach; I distinguish between intuitionist principled pluralism and societal value pluralism; and I show how both kinds of pluralism imply restrictions on how conclusions can be made. No substantive moral decision
principles can be allowed. Still, I argue, decision principles of a more epistemological or procedural character can be acceptable
even within pluralism. The pragmatist principle of inquiry is defended as an account of moral problem solving compatible with
both principled pluralism and value pluralism. When an ethical matrix is used within such a participatory inquiry process
substantive conclusions can be drawn. 相似文献
948.
Annika Porsborg Nielsen Jesper Lassen Peter Sandøe 《Journal of Agricultural and Environmental Ethics》2007,20(1):13-35
Over recent decades, public participation in technology assessment has spread internationally as an attempt to overcome or
prevent societal conflicts over controversial technologies. One outcome of this new surge in public consultation initiatives
has been the increased use of participatory consensus conferences in a number of countries. Existing evaluations of consensus
conferences tend to focus on the modes of organization, as well as the outcomes, both procedural and substantial, of the conferences
they examine. Such evaluations seem to rest on the assumption that this type of procedure has universally agreed goals and
meanings, and that therefore consensus conferences can readily be interpreted and applied across national boundaries. This
article challenges this approach to consensus conferences. The core of the article is a study of national differences in ideas
about what constitutes legitimate goals for participatory arrangements. The study looks at three consensus conferences on
GMOs, which took place in France, Norway, and Denmark. Drawing on this study, the article discusses the ways in which interpretations
of the concept of participation; the value attributed to lay knowledge vs. technical expertise; as well as ideas about the
role of the layperson, are all questions that prompt entirely different answers from country to country. Further, the article
analyses these national differences within a theoretical framework of notions of democratic legitimacy. 相似文献
949.
James F. Fox Athanasios N. Papanicolaou 《Journal of the American Water Resources Association》2007,43(4):1047-1064
Abstract: Tracer studies are needed to better understand watershed soil erosion and calibrate watershed erosion models. For the first time, stable nitrogen and carbon isotopes (δ15N and δ13C) and the carbon to nitrogen atomic ratio (C/N) natural tracers are used to investigate temporal and spatial variability of erosion processes within a sub‐watershed. Temporal variability was assessed by comparing δ15N, δ13C, and C/N of eroded‐soils from a non‐equilibrium erosion event immediately following freezing and thawing of surface soils with two erosion events characterized by equilibrium conditions with erosion downcutting. Spatial variability was assessed for the equilibrium events by using the δ15N and δ13C signatures of eroded‐soils to measure the fraction of eroded‐soil derived from rill/interrill erosion on upland hillslopes as compared to headcut erosion on floodplains. In order to perform this study, a number of tasks were carried out including: (1) sampling source‐soils from upland hillslopes and floodplains, (2) sampling eroded‐soils with an in situ trap in the stream of the sub‐watershed, (3) isotopic and elemental analysis of the samples using isotope ratio mass spectrometry, (4) fractioning eroded‐soil to its upland rill/interrill and floodplain headcut end‐members using an unmixing model within a Bayesian Markov Chain Monte Carlo framework, and (5) evaluating tracer unmixing model results by comparison with process‐based erosion prediction models for rill/interrill and headcut erosion processes. Results showed that finer soil particles eroded during the non‐equilibrium event were enriched in δ15N and δ13C tracers and depleted in C/N tracer relative to coarser soil particles eroded during the equilibrium events. Correlation of tracer signature with soil particle size was explainable based on known biogeochemical processes. δ15N and δ13C were also able to distinguish between upland rill/interrill erosion and floodplain headcut erosion, which was due to different plant cover at the erosion sources. Results from the tracer unmixing model highlighted future needs for coupling rill/interrill and headcut erosion prediction models. 相似文献
950.
J. Karnesky P. Chatterjee F. Tamanini S. Dorofeev 《Journal of Loss Prevention in the Process Industries》2007,20(4-6):447-454
A three-dimensional gasdynamic model with constant burning rate is applied for the prediction of the maximum pressure rise from gaseous combustion in vented enclosures. A series of calculations for an enclosure with aspect ratio close to unity are presented. Both cases with and without obstacles in the enclosure are considered. Results of calculations are compared with a simple 0D solution for spherical vessels. It is shown that, in cases without obstacles, the 0D solution for the maximum reduced overpressures is close to the predictions of the detailed modeling. In cases with obstacles, the detailed simulation gives significantly higher overpressures than those from the 0D model. However, in all the cases the reduced pressures are correlated well with the maximum flame surface area. 相似文献