全文获取类型
收费全文 | 185篇 |
免费 | 2篇 |
专业分类
安全科学 | 6篇 |
废物处理 | 7篇 |
环保管理 | 15篇 |
综合类 | 56篇 |
基础理论 | 32篇 |
环境理论 | 1篇 |
污染及防治 | 55篇 |
评价与监测 | 12篇 |
社会与环境 | 2篇 |
灾害及防治 | 1篇 |
出版年
2021年 | 3篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 8篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 7篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 6篇 |
2005年 | 10篇 |
2004年 | 4篇 |
2002年 | 9篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1979年 | 3篇 |
1977年 | 4篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 3篇 |
1963年 | 2篇 |
1962年 | 1篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1955年 | 3篇 |
1954年 | 1篇 |
1931年 | 1篇 |
排序方式: 共有187条查询结果,搜索用时 46 毫秒
81.
Increases in biodiversity can result from an increase in species richness, as well as from a higher genetic diversity within species. Intraspecific genetic diversity, measured as the number of genotypes, can enhance plant primary productivity and have cascading effects at higher trophic levels, such as an increase in herbivore and predator richness. The positive effects of genotypic mixtures are not only determined by additive effects, but also by interactions among genotypes, such as facilitation or inhibition. However, so far there has been no effort to predict the extent of such effects. In this study, we address the question of whether the magnitude of the effect of genotype number on population performance can be explained by the extent of dissimilarity in key traits among genotypes in a mixture. We examine the relative contribution of genotype number and phenotypic dissimilarity among genotypes to population performance of the soil arthropod, Orchesella cincta. Nearly homogeneous genotypes were created from inbred isofemale lines. Phenotypic dissimilarity among genotypes was assessed in terms of three life-history traits that are associated with population growth rate, i.e., egg size, egg development time, and juvenile growth rate. A microcosm experiment with genotype mixtures consisting of one, two, four, and eight genotypes, showed that genotypic richness strongly increased population size and biomass production and was associated with greater net diversity effects. Most importantly, there was a positive log-linear relationship between phenotypic dissimilarity in a mixture and the net diversity effects for juvenile population size and total biomass. In other words, the degree of phenotypic dissimilarity among genotypes determined the magnitude of the genotypic richness effect, although this relationship leveled off at higher values of phenotypic dissimilarity. Although the exact mechanisms responsible for these effects are currently unknown, similar advantages of trait dissimilarity have been found among species. Hence, to better understand population performance, genotype number and phenotypic dissimilarity should be considered collectively. 相似文献
82.
Delgado-Alvarez Carolina Guadalupe Ruelas-Inzunza Jorge Osuna-Martínez Carmen Cristina Bergés-Tiznado Magdalena Elizabeth Escobar-Sánchez Ofelia Ocampo-Rodríguez Pedro Octavio Soto-Romero Karen Lizbeth Garzón-Raygoza Nancy Lorena Aguilar-Júarez Marisela Osuna-López José Isidro Frías-Espericueta Martín 《Environmental science and pollution research international》2021,28(9):10909-10917
Environmental Science and Pollution Research - Mercury and selenium concentrations and Se:Hg molar ratio in edible muscle and hepatopancreas of the crab Callinectes arcuatus from coastal lagoons of... 相似文献
83.
Bergés-Tiznado Magdalena E. Márquez-Farías J. Fernando Osuna-Martínez C. Cristina Páez-Osuna Federico 《Environmental geochemistry and health》2021,43(9):3441-3455
Environmental Geochemistry and Health - Distribution of arsenic (As) in tissues and gonads of the Indo-Pacific sailfish Istiophorus platypterus and the dolphinfish Coryphaena hippurus from the SE... 相似文献
84.
Eric D. Crandall Rachel H. Toczydlowski Libby Liggins Ann E. Holmes Maryam Ghoojaei Michelle R. Gaither Briana E. Wham Andrea L. Pritt Cory Noble Tanner J. Anderson Randi L. Barton Justin T. Berg Sofia G. Beskid Alonso Delgado Emily Farrell Nan Himmelsbach Samantha R. Queeno Thienthanh Trinh Courtney Weyand Andrew Bentley John Deck Cynthia Riginos Gideon S. Bradburd Robert J. Toonen 《Conservation biology》2023,37(4):e14061
Genetic diversity within species represents a fundamental yet underappreciated level of biodiversity. Because genetic diversity can indicate species resilience to changing climate, its measurement is relevant to many national and global conservation policy targets. Many studies produce large amounts of genome-scale genetic diversity data for wild populations, but most (87%) do not include the associated spatial and temporal metadata necessary for them to be reused in monitoring programs or for acknowledging the sovereignty of nations or Indigenous peoples. We undertook a distributed datathon to quantify the availability of these missing metadata and to test the hypothesis that their availability decays with time. We also worked to remediate missing metadata by extracting them from associated published papers, online repositories, and direct communication with authors. Starting with 848 candidate genomic data sets (reduced representation and whole genome) from the International Nucleotide Sequence Database Collaboration, we determined that 561 contained mostly samples from wild populations. We successfully restored spatiotemporal metadata for 78% of these 561 data sets (n = 440 data sets with data on 45,105 individuals from 762 species in 17 phyla). Examining papers and online repositories was much more fruitful than contacting 351 authors, who replied to our email requests 45% of the time. Overall, 23% of our email queries to authors unearthed useful metadata. The probability of retrieving spatiotemporal metadata declined significantly as age of the data set increased. There was a 13.5% yearly decrease in metadata associated with published papers or online repositories and up to a 22% yearly decrease in metadata that were only available from authors. This rapid decay in metadata availability, mirrored in studies of other types of biological data, should motivate swift updates to data-sharing policies and researcher practices to ensure that the valuable context provided by metadata is not lost to conservation science forever. 相似文献
85.
86.
87.
88.
Hermann Berg 《Die Naturwissenschaften》1960,47(14):320-321
89.
This paper presents a study of recycling stations in the municipality of Borl?nge, Sweden. The main objectives were to measure volume weights of recyclables, to facilitate future planning of collection intervals and bin/container volume, and to investigate the general attitudes among the public towards waste management in general and recycling stations in particular. Volume weights measured in bins/containers were: paper/newsprint: 297 kg/m3, glass packaging: 297 kg/m3, metal packaging: 81.7 kg/m3, paper packaging: 27.8 kg/m3, plastic packaging: 28.1 kg/m3. The recycling stations have been in use since 1994. Most visitors (90%) arrived by car but said the visit to the recycling station was not the main purpose of the trip. The results from the interviews indicated that the people who use the recycling stations have found ways to incorporate waste sorting into their everyday lives, with the help of information, design of the collection system and environmental concerns. 相似文献
90.
This article examines the role of building trust in Humanitarian Mine Action (HMA). The role of trust following a mine-clearance operation is largely an unexplored region. Drawing on case studies from Angola, Mozambique and Afghanistan, the article explores how trust can be understood in the context of humanitarian initiatives such as landmine clearance, and outlines the challenges associated with building trust among populations with experience of armed conflict. Because trust is difficult to re-establish following a war, the argument presented here suggests that one way in which this can be done is through building relationships at the organisational and interpersonal levels. The analysis reviews specific measures that mine-action agencies have used to build trust, looking at the strengths and weaknesses of different approaches. The analysis concludes by suggesting general guidelines for how mine-action practitioners can facilitate trust, and by outlining some promising avenues for future research. 相似文献