全文获取类型
收费全文 | 814篇 |
免费 | 24篇 |
国内免费 | 70篇 |
专业分类
安全科学 | 45篇 |
废物处理 | 38篇 |
环保管理 | 76篇 |
综合类 | 235篇 |
基础理论 | 174篇 |
环境理论 | 4篇 |
污染及防治 | 235篇 |
评价与监测 | 41篇 |
社会与环境 | 50篇 |
灾害及防治 | 10篇 |
出版年
2024年 | 3篇 |
2023年 | 13篇 |
2022年 | 20篇 |
2021年 | 20篇 |
2020年 | 19篇 |
2019年 | 13篇 |
2018年 | 35篇 |
2017年 | 28篇 |
2016年 | 28篇 |
2015年 | 26篇 |
2014年 | 30篇 |
2013年 | 49篇 |
2012年 | 34篇 |
2011年 | 57篇 |
2010年 | 41篇 |
2009年 | 43篇 |
2008年 | 40篇 |
2007年 | 52篇 |
2006年 | 39篇 |
2005年 | 26篇 |
2004年 | 38篇 |
2003年 | 27篇 |
2002年 | 31篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 16篇 |
1997年 | 18篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1994年 | 15篇 |
1993年 | 7篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1980年 | 3篇 |
1976年 | 3篇 |
1966年 | 3篇 |
1964年 | 3篇 |
1963年 | 3篇 |
1962年 | 2篇 |
1961年 | 3篇 |
1960年 | 3篇 |
1959年 | 2篇 |
1957年 | 5篇 |
1956年 | 6篇 |
1955年 | 4篇 |
1954年 | 2篇 |
1951年 | 3篇 |
1922年 | 3篇 |
排序方式: 共有908条查询结果,搜索用时 343 毫秒
491.
Interactions among Frugivores and Fleshy Fruit Trees in a Philippine Submontane Rainforest 总被引:3,自引:0,他引:3
Abstract: We assessed the potential effect of frugivore extinctions on forest regeneration in the North Negros Forest Reserve, a forest fragment that is one of the last remaining wet tropical rainforest ecosystems in the biogeographic region of the central Philippine Islands. We evaluated foraging observations of 19 species of birds, fruit bats, and other mammals in three successional habitats and identified tree species that are potentially at risk because their seeds are dispersed by frugivores that are seriously endangered. The relative abundance of zoochorous trees in this forest community was exceptionally high (80%), suggesting that the process of forest regeneration will change drastically if endangered frugivores are hunted to extinction. We grouped 45 tree species as early-, mid-, or late-successional species based on their population structure and we demonstrated that early-successional tree species were visited by a wide spectrum of frugivores, whereas mid- and late-successional species were visited mostly by hornbills (Bucerotidae) and fruit pigeons (Columbidae). Late-successional tree species were most specialized with respect to dispersers and could therefore be susceptible to extinction. We recommend tree species that could be useful for assisted natural regeneration projects in the reserve because they are visited by a variety of frugivores. Of those, we recommend early-successional trees for open-field plantations and mid-successional tree species for enrichment plantings. 相似文献
492.
Andreas J. Schindelin Fritz H. Frimmel 《Environmental science and pollution research international》2000,7(4):205-210
By means of simulated sunlight, the influence of natural organic matter (NOM) on the photochemical degradation of halogenated
pesticides in the absence and presence of nitrate as a precursor of the highly reactive OH radicals in aqueous solutions and
freshwater was investigated. Solutions of dichlorprop or terbutylazine (a) in phosphate-buffered demineralized water containing
nitrate and/or NOM and (b) in natural freshwaters were irradiated by a 1000-W Xe short-arc lamp. The collimated beam was filtered
using a combination of optical filters (WG 320 and WG 295) to simulate the solar spectrum under summer midday conditions.
In the absence of nitrate and NOM, the pesticides were degraded photolytically by simulated sunlight. The degradation rates
depended on the absorption spectrum in the UVB range and the quantum yield of the degradation. The photochemical degradation
of the pesticides was faster in the presence of nitrate due to the sunlight-induced formation of OH radicals. In the absence
of nitrate, low concentrations of NOM of a brownwater lake accelerated the degradation due to the formation of reactive species
by NOM. At higher concentrations of NOM, the inner filter effect of NOM lowered the degradation rates. In the presence of
50 mg l−1 nitrate, NOM decreased the degradation rate significantly. In case the natural water samples were used as a matrix
for the experiments (nitrate concentrations between 2 mg l−1 and 15 mg l−1, DOC concentrations below 2.3 mg l−1), NOM acted
mainly as a radiation filter and as a scavenger of OH radicals. As a consequence, in most freshwater systems, the accelerating
effect of NOM by the formation of reactive species is of minor importance compared to the inner filter effect and to radical
scavenging. 相似文献
493.
Iordanidis A Buckman J Triantafyllou AG Asvesta A 《Environmental geochemistry and health》2008,30(5):391-405
The aim of this study was to characterise individual airborne particles collected from the Ptolemais-Kozani region (Western Macedonia), northern Greece. Throughout a 1-year period (March 2003 to February 2004), we collected several filters that captured airborne particles at seven sampling sites distributed throughout the area. The airborne particles captured on the filters were then characterised by environmental scanning electron microscopy (ESEM) coupled with energy-dispersive X-ray analysis (EDX). The particles were categorised as geogenic, biogenic and anthropogenic. The main anthropogenic airborne particles were fly ash (released from lignite-fired power plants) and carbonaceous (soot and char) and metalliferous (mainly iron- and copper-enriched) particulates. We present here characteristic ESEM and EDX spectra for the airborne particles and underline the presence of characteristic primary and secondary sulphates. 相似文献
494.
Lasse Marohn Enno Prigge Karsten Zumholz Andreas Klügel Heike Anders Reinhold Hanel 《Marine Biology》2009,156(5):927-933
Otolith microchemistry is widely used as a tool to track individual migration pathways of diadromous fish under the assumption
that the elemental composition of fish otoliths is directly influenced by the physicochemical properties of the surrounding
water. Nevertheless, several endogenous factors are reported to affect element incorporation into fish otoliths and might
lead to misinterpretations of migration studies. This study experimentally examined the influence of eight different diets
on the microchemical composition of European eel (Anguilla anguilla) otoliths using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Seven natural prey types and one
artificial diet were fed during 8 weeks in freshwater circuits. Results show for the first time that food has no significant
influence on the incorporation of Na, Sr, Ba, Mg, Mn, Cu and Y into European eel otoliths. This indicates that the incorporation
of elements usually chosen for migration studies is not affected by diet and that individual feeding behaviour of A. anguilla will not lead to any misinterpretation of migration pathways. 相似文献
495.
496.
Despite the rapid growth of organizational research on subjective time, the extant literature is fragmented due to a lack of conceptual clarification and integration of temporal constructs. To address this fragmentation, we synthesize temporal research from both organizational behavior and adjacent disciplines (i.e., strategy, entrepreneurship, and organizational theory) and introduce a framework that allocates temporal constructs according to their basic conceptual nature (trait–state) and level of analysis (individual–collective). We employed the Linguistic Inquiry and Word Count text analysis to determine the trait–state property of the constructs and a coding method to determine their level of analysis. This framework categorizes four generic types of subjective time: individual temporal disposition, individual temporal state, collective temporal state, and collective temporal disposition. We clarify the conceptualizations of the temporal constructs belonging to each of the four archetypes of subjective time and review their key findings in the organizational literature. Based on this integrative framework, we identify critical knowledge gaps in the current state of research and chart a future agenda with specific suggestions. 相似文献
497.
Juan Arteaga Pablo Ochoa Andreas Fries Jan Boll 《Journal of the American Water Resources Association》2020,56(2):270-282
Integrated watershed management (IWM) is a priority, especially in semiarid regions that are concurrently affected by population growth, land use change, soil erosion, and poor governance. In developing countries, IWM is often done without any support tool, scientific data, or deep knowledge of territory characteristics. The aim of this study was to present a case study to apply a decision support tool to prioritize areas for territory management. A simple, quantitative multi‐criteria analysis was applied in a semiarid basin of the Ecuadorian Andes to identify the zones of greatest concern for implementation of resource conservation and management practices at a local and regional scale. In addition to describing the current state of the conditions of this basin, our results suggest scenarios of change in relation to official population projections based on spatial analysis of land use change. Analysis resulted in a scattered distribution of priority values within the watershed, so a hierarchical rule was incorporated to define priorities at the subwatershed (SW) scale. Our analysis identified four SW of very high priority and urgent need to implement management practices. Based on projections of future change due to population growth and land cover change, the number of subbasins that require more attention was doubled. Finally, this study includes zones for management or conservation of the land, according to the Sustainable Development Goals. 相似文献
498.
Emma Wiik Julia P. G. Jones Edwin Pynegar Patrick Bottazzi Nigel Asquith James Gibbons Andreas Kontoleon 《Conservation biology》2020,34(5):1076-1088
Conservation science needs more high-quality impact evaluations, especially ones that explore mechanisms of success or failure. Randomized control trials (RCTs) provide particularly robust evidence of the effectiveness of interventions (although they have been criticized as reductionist and unable to provide insights into mechanisms), but there have been few such experiments investigating conservation at the landscape scale. We explored the impact of Watershared, an incentive-based conservation program in the Bolivian Andes, with one of the few RCTs of landscape-scale conservation in existence. There is strong interest in such incentive-based conservation approaches as some argue they can avoid negative social impacts sometimes associated with protected areas. We focused on social and environmental outcomes based on responses from a household survey in 129 communities randomly allocated to control or treatment (conducted both at the baseline in 2010 and repeated in 2015–2016). We controlled for incomplete program uptake by combining standard RCT analysis with matching methods and investigated mechanisms by exploring intermediate and ultimate outcomes according to the underlying theory of change. Previous analyses, focused on single biophysical outcomes, showed that over its first 5 years Watershared did not slow deforestation or improve water quality at the landscape scale. We found that Watershared influenced some outcomes measured using the survey, but the effects were complex, and some were unexpected. We thus demonstrated how RCTs can provide insights into the pathways of impact, as well as whether an intervention has impact. This paper, one of the first registered reports in conservation science, demonstrates how preregistration can help make complex research designs more transparent, avoid cherry picking, and reduce publication bias. 相似文献
499.
Henne Paul D. Bigalke Moritz Büntgen Ulf Colombaroli Daniele Conedera Marco Feller Urs Frank David Fuhrer Jürg Grosjean Martin Heiri Oliver Luterbacher Jürg Mestrot Adrien Rigling Andreas Rössler Ole Rohr Christian Rutishauser This Schwikowski Margit Stampfli Andreas Szidat Sönke Theurillat Jean-Paul Weingartner Rolf Wilcke Wolfgang Tinner Willy 《Regional Environmental Change》2018,18(1):205-221
Regional Environmental Change - Planning for the future requires a detailed understanding of how climate change affects a wide range of systems at spatial scales that are relevant to humans.... 相似文献
500.
Bernhard Forchtner Andreas Kroneder David Wetzel 《Environmental Communication: A Journal of Nature and Culture》2018,12(5):589-604
This article explores climate-change communication by the German far right – spanning a continuum which ranges from anti-liberal democracy radical-right populists, to the extreme right and to anti-democratic neo-Nazis – and asks: how do these actors articulate the phenomenon of climate change? In responding to this question, we conduct a discourse network analysis which identifies relations between actors, objects, phenomena, and processes, and points out differences/similarities across a continuum of exemplary far-right sources. The investigated actors put forward a rather skeptical climate change narrative, even though differences exist as the significance attached to the Volk and its sovereignty, rooted in far-right ideology, sometimes overrides, and sometimes is in harmony with, their ideological-driven affinity with nature protection. We thus contribute to the growing body of knowledge on climate-change communication and, more specifically, on the link between ideology and climate-change skepticism. 相似文献