全文获取类型
收费全文 | 1179篇 |
免费 | 181篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 101篇 |
废物处理 | 93篇 |
环保管理 | 320篇 |
综合类 | 60篇 |
基础理论 | 423篇 |
环境理论 | 2篇 |
污染及防治 | 227篇 |
评价与监测 | 47篇 |
社会与环境 | 34篇 |
灾害及防治 | 59篇 |
出版年
2023年 | 4篇 |
2022年 | 13篇 |
2021年 | 19篇 |
2020年 | 14篇 |
2019年 | 53篇 |
2018年 | 77篇 |
2017年 | 44篇 |
2016年 | 71篇 |
2015年 | 56篇 |
2014年 | 75篇 |
2013年 | 257篇 |
2012年 | 61篇 |
2011年 | 88篇 |
2010年 | 72篇 |
2009年 | 60篇 |
2008年 | 60篇 |
2007年 | 46篇 |
2006年 | 39篇 |
2005年 | 34篇 |
2004年 | 30篇 |
2003年 | 37篇 |
2002年 | 39篇 |
2001年 | 27篇 |
2000年 | 26篇 |
1999年 | 15篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 8篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1366条查询结果,搜索用时 15 毫秒
1.
Understanding implications of consumer behavior for wildlife farming and sustainable wildlife trade
下载免费PDF全文
![点击此处可从《Conservation biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A. Nuno J. M. Blumenthal T. J. Austin J. Bothwell G. Ebanks‐Petrie B. J. Godley A. C. Broderick 《Conservation biology》2018,32(2):390-400
Unsustainable wildlife trade affects biodiversity and the livelihoods of communities dependent upon those resources. Wildlife farming has been proposed to promote sustainable trade, but characterizing markets and understanding consumer behavior remain neglected but essential steps in the design and evaluation of such operations. We used sea turtle trade in the Cayman Islands, where turtles have been farm raised for human consumption for almost 50 years, as a case study to explore consumer preferences toward wild‐sourced (illegal) and farmed (legal) products and potential conservation implications. Combining methods innovatively (including indirect questioning and choice experiments), we conducted a nationwide trade assessment through in‐person interviews from September to December 2014. Households were randomly selected using disproportionate stratified sampling, and responses were weighted based on district population size. We approached 597 individuals, of which 37 (6.2%) refused to participate. Although 30% of households had consumed turtle in the previous 12 months, the purchase and consumption of wild products was rare (e.g., 64–742 resident households consumed wild turtle meat [i.e., 0.3–3.5% of households] but represented a large threat to wild turtles in the area due to their reduced populations). Differences among groups of consumers were marked, as identified through choice experiments, and price and source of product played important roles in their decisions. Despite the long‐term practice of farming turtles, 13.5% of consumers showed a strong preference for wild products, which demonstrates the limitations of wildlife farming as a single tool for sustainable wildlife trade. By using a combination of indirect questioning, choice experiments, and sales data to investigate demand for wildlife products, we obtained insights about consumer behavior that can be used to develop conservation‐demand‐focused initiatives. Lack of data from long‐term social–ecological assessments hinders the evaluation of and learning from wildlife farming. This information is key to understanding under which conditions different interventions (e.g., bans, wildlife farming, social marketing) are likely to succeed. 相似文献
2.
Fishing‐gear restrictions and biomass gains for coral reef fishes in marine protected areas
下载免费PDF全文
![点击此处可从《Conservation biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Stuart J. Campbell Graham J. Edgar Rick D. Stuart‐Smith German Soler Amanda E. Bates 《Conservation biology》2018,32(2):401-410
Considerable empirical evidence supports recovery of reef fish populations with fishery closures. In countries where full exclusion of people from fishing may be perceived as inequitable, fishing‐gear restrictions on nonselective and destructive gears may offer socially relevant management alternatives to build recovery of fish biomass. Even so, few researchers have statistically compared the responses of tropical reef fisheries to alternative management strategies. We tested for the effects of fishery closures and fishing gear restrictions on tropical reef fish biomass at the community and family level. We conducted 1,396 underwater surveys at 617 unique sites across a spatial hierarchy within 22 global marine ecoregions that represented 5 realms. We compared total biomass across local fish assemblages and among 20 families of reef fishes inside marine protected areas (MPAs) with different fishing restrictions: no‐take, hook‐and‐line fishing only, several fishing gears allowed, and sites open to all fishing gears. We included a further category representing remote sites, where fishing pressure is low. As expected, full fishery closures, (i.e., no‐take zones) most benefited community‐ and family‐level fish biomass in comparison with restrictions on fishing gears and openly fished sites. Although biomass responses to fishery closures were highly variable across families, some fishery targets (e.g., Carcharhinidae and Lutjanidae) responded positively to multiple restrictions on fishing gears (i.e., where gears other than hook and line were not permitted). Remoteness also positively affected the response of community‐level fish biomass and many fish families. Our findings provide strong support for the role of fishing restrictions in building recovery of fish biomass and indicate important interactions among fishing‐gear types that affect biomass of a diverse set of reef fish families. 相似文献
3.
4.
5.
6.
Stoichev T Rodriguez Martin-Doimeadios RC Amouroux D Molenat N Donard OF 《Journal of environmental monitoring : JEM》2002,4(4):517-521
The concentration levels of mercury (Hg) species in natural water samples are usually low. Consequently, accurate analysis with low detection limits is still a major problem. In this work, a method was applied for the simultaneous direct determination of dissolved mercury species in water samples by on-line hydride generation (HG), cryogenic trapping (CT), gas chromatography (GC) and detection by atomic fluorescence spectrometry (AFS). The suitability of the method for real samples with different organic matter and chloride contents was evaluated by recovery experiments in synthetic and natural spiked water samples. The HG method was compared with other current available methods for mercury analysis with respect to the different fraction of mercury analysed, i.e. 'reactive', 'reducible' or total. HG derivatization and SnCl2 reduction (with and without previous oxidation with BrCl) were applied to synthetic and natural (spiked and non-spiked) water samples. The influence of chloride and dissolved organic matter concentrations was studied. The results suggest that the HG procedure is suitable for the simultaneous determination of Hg2+ and MeHg+ in surface water samples. Inorganic mercury analysed by HG (i.e. reducible) is close to the total inorganic mercury. 相似文献
7.
Rodriguez MJ Vinette Y Sérodes JB Bouchard C 《Environmental monitoring and assessment》2003,89(1):69-93
The levels of trihalomethanes (THMs) – the main species of by-product from water chlorination – were monitored in thedistribution systems of the five major drinking water utilitiesof the greater area of Québec City in order to investigate andmodel their occurrence on a spatial and seasonal basis. Data forTHMs and other water quality and operational parametersassociated with their formation were generated through a 16 monthsampling program involving several sites representing variablewater residence times, from the plant to the system extremity.The results demonstrate that the differences in measured THMlevels between the five utilities are mainly due to the variablequality of raw waters, the type of water treatment process beingused and the type and levels of applied disinfectant. Dependingon the utility, average THM levels were from 1.3 to 2.5 timeshigher in the system extremities than in the water leaving thetreatment plant. Also, average levels of THMs measured in summerat the distribution system extremities were, depending on theutility, from 2.5 to 5 times higher than the average levelsmeasured in winter. The seasonal differences were found to besignificantly greater than those observed by others in waterutilities in the United States and Europe and are explained inlarge part by the considerable changes, over the year, in thequality and temperature of surface waters in Southern Québec. Forthe five utilities under study, multivariate regression modelswere developed in order to predict spatial and seasonalvariations of THMs. Both residual chlorine demand and temperaturewere found to be better, statistically, as predictors for THMoccurrence. The usefulness of the developed models for routineand long term water quality management, as well as for assessmentof human exposure to THMs, are also discussed. 相似文献
8.
K. G. Willis Malcolm Newson Sonja Boehmer‐Christiansen 《Journal of Environmental Planning and Management》1994,37(2):243-247
Cost Benefit Analysis of Environmental Change
Per‐Olov Johansson
Cambridge, Cambridge University Press, 1993, 232 pp., £13.95
Computerised Environmental Modelling: A Practical Introduction using Excel
J. Hardisty, D. M. Taylor & S. E. Metcalfe
Chichester, Wiley, 1993, 204 pp., £14.95
Keeping Pace with Science and Engineering: Case Studies in Environmental Regulation
Washington DC, US National Academy of Engineering, 1993
World Without End: Economics, Environment and Sustainable Development
D. W. Pearce & J. J. Warford
Oxford University Press, New York, 1993, 440 pp., £35.95 相似文献
9.
Manuel Ruiz-Pérez Mauro Almeida Sonya Dewi Eliza Mara Lozano Costa Mariana Ciavatta Pantoja Atie Puntodewo Augusto de Arruda Postigo Alexandre Goulart de Andrade 盛岩 《Ambio-人类环境杂志》2005,34(3):214-219
开发利用型保护区是同时满足保护和发展目标的一项创举,在巴西,建立开发利用型保护区最初是作为森林居民进行土地斗争的一部分.虽然这个概念已普及,并且人们也在尝试把它推广到其他热带地区,但却很少有人对开发利用型保护区项目在保护和发展方面取得的成绩进行综合分析.我们对1990年在巴西建立的第一个开发利用型保护区的森林砍伐、人口和社会经济变化进行了详细分析.保护区内的森林覆盖度一直相当稳定.人口数量稍有下降,并且在保护区内发生了一些居住地迁移.现金经济收入的主要来源由原来的橡胶生产转变为多种农作物和家畜综合生产,非农业收入也大幅度增加.我们认为该开发利用型保护区代表了一种不断变化的环境,在其建立之初的10年中,开发利用型保护区对保护和发展起了积极促进作用. 相似文献
10.
Alessandro Ghidini MD Manuel Alvarez Gittel Silverberg Eugene Ainbender Charles J. Lockwood 《黑龙江环境通报》1994,14(7):599-602
Congenital nephrosis is an autosomal recessive disorder requiring neonatal renal transplant for survival. The postnatal diagnosis rests upon the electron microscopic evaluation of the epithelial foot processes and basal membrane of the glomeruli. The prenatal diagnosis can be suspected in the presence of a positive family history with an amniotic fluid (AF) alpha-fetoprotein level greater than 5 standard deviations (SD) above the population mean accompanied by a negative AF acetylcholinesterase, absent haemoglobin F, and an unremarkable fetal sonographic examination. We reviewed our series of seven cases of congenital nephrosis fulfilling the above criteria; four cases had negative family histories, and in two cases the diagnosis of congenital nephrosis was further supported by the presence of elevated AF albumin concentrations. We conclude that (1) the prenatal diagnosis of congenital nephrosis is feasible in a low-risk population, and (2) an elevated AF albumin concentration may represent an additional marker for the diagnosis of congenital nephrosis, even though false-negative results have been reported. 相似文献