全文获取类型
收费全文 | 2963篇 |
免费 | 28篇 |
国内免费 | 40篇 |
专业分类
安全科学 | 105篇 |
废物处理 | 89篇 |
环保管理 | 375篇 |
综合类 | 608篇 |
基础理论 | 645篇 |
环境理论 | 2篇 |
污染及防治 | 849篇 |
评价与监测 | 185篇 |
社会与环境 | 150篇 |
灾害及防治 | 23篇 |
出版年
2023年 | 27篇 |
2022年 | 23篇 |
2021年 | 38篇 |
2020年 | 30篇 |
2019年 | 38篇 |
2018年 | 69篇 |
2017年 | 70篇 |
2016年 | 82篇 |
2015年 | 97篇 |
2014年 | 94篇 |
2013年 | 189篇 |
2012年 | 119篇 |
2011年 | 195篇 |
2010年 | 155篇 |
2009年 | 177篇 |
2008年 | 172篇 |
2007年 | 168篇 |
2006年 | 121篇 |
2005年 | 93篇 |
2004年 | 116篇 |
2003年 | 83篇 |
2002年 | 105篇 |
2001年 | 87篇 |
2000年 | 55篇 |
1999年 | 25篇 |
1998年 | 34篇 |
1997年 | 34篇 |
1996年 | 32篇 |
1995年 | 39篇 |
1994年 | 38篇 |
1993年 | 15篇 |
1992年 | 30篇 |
1991年 | 39篇 |
1990年 | 21篇 |
1989年 | 27篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 13篇 |
1982年 | 20篇 |
1981年 | 16篇 |
1980年 | 8篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1970年 | 12篇 |
1969年 | 8篇 |
1965年 | 10篇 |
1960年 | 10篇 |
1956年 | 8篇 |
排序方式: 共有3031条查询结果,搜索用时 15 毫秒
71.
A. S. van Jaarsveld 《国际发展与全球生态学杂志》2013,20(2):15-37
SUMMARY A quantitative method which can be used to gauge the sustainability of existing socio-cultural, economic and environmental constructs is proposed. An underlying assumption of the approach is that a co-evolutionary relationship exists between social, cultural, economic and environmental systems and that these cannot be addressed in a reductionist and deterministic manner. The method focuses on both broad trends and patterns of variance in a multivariate data matrix, it allows the identification of dominant trends as well as underlying tensions, does not treat socio-cultural, economic and environmental heterogeneity as statistical noise and can be applied at different administrative scales. Furthermore, it may be used to identify potential sources of human insecurity, factors that may affect the probability of positive human survival, developmental patterns at odds with the established values system of civil society that can be targeted for political action, and to inform public debate. In addition, the method can be used to identify unexpected synergies between variables and may serve as an early warning system for regional planners. 相似文献
72.
This report presents the results of a research programme designed to examine the engineering and environmental acceptability of stabilizing municipal solid waste (MSW) combustor ash for artificial reef construction. Municipal solid waste combustor ash was combined with Portland cement to form solid blocks using conventional construction block making technology. the resultant stabilized combustor ash (SCA) blocks were used to construct an artificial habitat in Conscience Bay, Long Island Sound, New York and compared to identical concrete blocks, fabricated using natural aggregates. Over a 4.5 year period divers periodically returned to the site to monitor the interaction of SCA blocks with the marine environment and compare the performance of these blocks with the concrete control blocks. Results show that the SCA blocks retain their strength after prolonged sea water exposure. Contaminants of environmental concern, including metals, dioxins and furans, were retained within the cementitious matrix of the SCA blocks after prolonged sea water submersion. in addition, organisms growing on the surfaces of the SCA blocks did not accumulate contaminants from the blocks. 相似文献
73.
Christian Sonne PhD DVM VMD MVSc Rossana Bossi Rune Dietz Pall S. Leifsson Frank F. Rigét Erik W. Born 《毒物与环境化学》2013,95(2):275-283
In this study, residual concentrations of chlorpyrifos (CPF) were determined in feed (40) and fodder (25) samples collected from various locations of Tarai region of Uttarakhand. For extracting residues, liquid–liquid partition followed by alumina column clean up was used and the detection and quantification of residues was undertaken with the help of high-performance liquid chromatography using C18 column and diode array detector at 220?nm. Of the total 40 feed samples analyzed, 7 (17.5%) samples were found positive for CPF with the mean residual concentration of 0.058?µg?g?1; while out of 25 fodder samples, CPF residues were detected in a single (4%) sample with residual concentration of 0.39?µg?g?1. However, none of the feed or fodder samples contained CPF residues above the prescribed limit. 相似文献
74.
75.
Caitlin E. Andrews Sandra H. Anderson Karin van der Walt Rose Thorogood John G. Ewen 《Conservation biology》2022,36(4):e13892
Conservation translocation is a common method for species recovery, for which one increasingly frequent objective is restoring lost ecological functions to promote ecosystem recovery. However, few conservation translocation programs explicitly state or monitor function as an objective, limiting the ability to test assumptions, learn from past efforts, and improve management. We evaluated whether translocations of hihi (Notiomystis cincta), a threatened New Zealand passerine, achieved their implicit objective of restoring lost pollination function. Through a pollinator-exclusion experiment, we quantified, with log response ratios (lnR), the effects of birds on fruit set and seed quality in hangehange (Geniostoma ligustrifolium), a native flowering shrub. We isolated the contributions of hihi by making comparisons across sites with and without hihi. Birds improved fruit set more at sites without hihi (lnR = 1.27) than sites with hihi (lnR = 0.50), suggesting other avian pollinators compensated for and even exceeded hihi contributions to fruit set. Although birds improved seed germination only at hihi sites (lnR = 0.22–0.41), plants at sites without hihi had germination rates similar to hihi sites because they produced 26% more filled seeds, regardless of pollination condition. Therefore, although our results showed hihi improved seed quality, they also highlighted the complexity of ecological functions. When an important species is lost, ecosystems may be able to achieve similar function through different means. Our results underscore the importance of stating and monitoring the ecological benefits of conservation translocations when functional restoration is a motivation to ensure these programs are achieving their objectives. 相似文献
76.
Land use and land cover changes are a major source of environmental degradation and therefore a serious issue in sustainable development studies and in the integrated assessment of environmental problems. In an attempt to understand part of the complexity of land use change we here aim to explore the ways in which economists deals with the land use issue. We argue that space is one of the forgotten items in economics. Economists often seem to ignore high-resolution spatial dynamics either because they are not considered as an important feature of the problem or out of habit. It seems as though there is a trade-off between spatial resolution and human behaviour in current applications. Certain types of models are capable of capturing the spatial complexity of urban and regional areas, for instance, by using cellular automata. Other types of land use models clearly have shortcomings where it concerns spatial detail. Dynamic modelling approaches do not guarantee a high spatial resolution.We propose to give more attention to agent based modelling as this type of modelling provides a specific connection between processes on micro level and macro-level spatial structures. 相似文献
77.
The utilisation of Social Impact Assessment (SIA) in Iran is analysed in terms of its policy context and its application in practice. Five case studies where SIA was employed in conjunction with Environmental Impact Assessments (EIA) for agricultural development projects are evaluated. In addition, the performance of the policy context is assessed. This research revealed that there are legal and institutional constraints to the effective functioning of SIA in Iran, and that there are deficiencies in the operating guidelines. There were serious problems associated with the way SIA was undertaken in all five case studies. Recommendations to improve the policy framework for the conduct of SIA are made. The recommendations advocate for a higher profile of SIA within legislation, for social issues to have greater emphasis in official guidelines for the conduct of EIA and SIA, and for a range of measures to increase the professionalism of SIA practice. 相似文献
78.
The comparison of increasing doses of a treatment to a negative control is frequently part of toxicological studies. For normally distributed data Williams (1971, 1972) introduced a maximum likelihood test under total order restriction. But until now there seems to have been no solution for the arbitrary unbalanced case. According to the idea proposed by Robertson et al. (1988) we will apply in this article the basic concept of Williams on the class of multiple contrast tests for the general unbalanced parametric set-up. Simulation results for size and power and two examples for estimating the minimal toxic dose (MTD) are given. 相似文献
79.
Andrés González Frank C. Schroeder Athula B. Attygalle Aleš Svatoš Jerrold Meinwald Thomas Eisner 《Chemoecology》1999,9(3):105-112
Summary. Female Photuris fireflies sequester defensive steroidal pyrones (lucibufagins) from male fireflies of the genus Photinus. Lucibufagin analyses of Photuris females and Photinus ignitus males show that the lucibufagin mixtures of predator and prey differ in their composition. Analyses of whole body extracts
showed that P. ignitus males contain a mixture of eight non-glycosylated lucibufagins, composed mostly of compounds with two oxygenated positions
in the steroidal A-ring (C-3, C-5). After feeding on P. ignitus males, Photuris females contain six major lucibufagins. Three of these compounds are not present in the prey, including the novel lucibufagin
glycoside 5β,11α-dihydroxy-12-oxo-3β-O-β-D-xylopyranosylbufalin, and two other lucibufagins with a trioxygenated A-ring (C-2,
C-3, C-5). These results indicate that Photuris females transform the sequestered lucibufagins both by glycosylation and oxidation, which could affect the systemic transportability
of these compounds due to an increase in their polarity.
Received 18 February 1999; accepted 19 April 1999. 相似文献
80.
L. E. C. Conceição T. van der Meeren J. A. J. Verreth M. S. Evjen D. F. Houlihan H. J. Fyhn 《Marine Biology》1997,129(2):255-265
The present paper studied the influence of different food regimes on the free amino acid (FAA) pool, the rate of protein
turnover, the flux of amino acids, and their relation to growth of larval turbot (Scophthalmus maximus L.) from first feeding until metamorphosis. The amino acid profile of protein was stable during the larval period although
some small, but significant, differences were found. Turbot larvae had proteins which were rich in leucine and aspartate,
and poor in glutamate, suggesting a high leucine requirement. The profile of the FAA pool was highly variable and quite different
from the amino acid profile in protein. The proportion of essential FAA decreased with development. High contents of free
tyrosine and phenylalanine were found on Day 3, while free taurine was present at high levels throughout the experimental
period. Larval growth rates were positively correlated with taurine levels, suggesting a dietary dependency for taurine and/or
sulphur amino acids. Reduced growth rates in Artemia-fed larvae were associated with lower levels of free methionine, indicating that this diet is deficient in methionine for
turbot larvae. Leucine might also be limiting turbot growth as the different diet organisms had lower levels of this amino
acid in the free pool than was found in the larval protein. A previously presented model was used to describe the flux of
amino acids in growing turbot larvae. The FAA pool was found to be small and variable. It was estimated that the daily dietary
amino acid intake might be up to ten times the larval FAA pool. In addition, protein synthesis and protein degradation might
daily remove and return, respectively, the equivalent of up to 20 and 10 times the size of the FAA pool. In an early phase
(Day 11) high growth rates were associated with a relatively low protein turnover, while at a later stage (Day 17), a much
higher turnover was observed.
Received: 19 March 1997 / Accepted: 14 April 1997 相似文献