全文获取类型
收费全文 | 457篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 39篇 |
废物处理 | 22篇 |
环保管理 | 82篇 |
综合类 | 103篇 |
基础理论 | 90篇 |
环境理论 | 2篇 |
污染及防治 | 79篇 |
评价与监测 | 25篇 |
社会与环境 | 16篇 |
灾害及防治 | 11篇 |
出版年
2023年 | 10篇 |
2021年 | 10篇 |
2020年 | 17篇 |
2019年 | 6篇 |
2018年 | 17篇 |
2017年 | 11篇 |
2016年 | 18篇 |
2015年 | 23篇 |
2014年 | 13篇 |
2013年 | 27篇 |
2012年 | 37篇 |
2011年 | 39篇 |
2010年 | 21篇 |
2009年 | 28篇 |
2008年 | 28篇 |
2007年 | 24篇 |
2006年 | 23篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 17篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 6篇 |
1994年 | 10篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 7篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有469条查询结果,搜索用时 93 毫秒
241.
242.
It has been proposed that the common West Coast limpet, Lottia digitalis, is actually the northern counterpart of a cryptic species duo including, Lottia austrodigitalis. Allele frequency differences between southern and northern populations at two polymorphic enzyme loci provided the basis
for this claim. Due to lack of further evidence, L. austrodigitalis is still largely unrecognized in the literature. Seven additional enzyme loci were examined from populations in proposed
zones of allopatry and sympatry to determine the existence of L. austrodigitalis as a sibling species to L. digitalis. Significant allele frequency differences were found at five enzyme loci between populations in Laguna Beach, southern California,
and Bodega Bay, northern California; strongly supporting the existence of separate species. Both species exhibit two microhabitat
morphotypes, a gooseneck barnacle morph in the mid-intertidal zone and a rock morph in the high-intertidal zone. In sympatry,
L. austrodigitalis was more abundant higher in the intertidal on rocks, whereas L. digitalis was more abundant lower in the intertidal on barnacles. This finding supports earlier claims of microhabitat partitioning
in this sibling species pair. In addition to this finding, the transition zone between the species was found to have shifted
substantially northward in only two decades, from Monterey Peninsula, CA to near Pigeon Point, CA, where L. digitalis previously dominated. 相似文献
243.
Contaminant concentrations in groundwater are typically analyzed using traditional laboratory analytical procedures approved by the Environmental Protection Agency (EPA) or state regulatory agencies. The use of off‐site laboratories provides very high‐quality water quality data at a relatively high cost in terms of time and money. Yet there are many instances when it is desirable to have water quality data measured in the field. The field methods for measuring water quality typically cost much less than the corresponding laboratory methods. However, the usability of the field data may be uncertain when the results are qualitatively compared to duplicate laboratory results. Groundwater samples collected during a groundwater circulation well pilot study were analyzed using field kits to measure concentrations of trichloroethylene (TCE) and the explosive compound known as RDX. A subset of the samples was split for duplicate laboratory analysis. Linear regression analysis and relative percent difference analysis were performed on the duplicate results to evaluate the comparability of the field and laboratory data. The data analyses were also used to evaluate the concept that the field kits were more accurate for specific concentration ranges, as well as the concept the field kit results would improve as field personnel gained experience with the field analysis procedures. © 2002 Wiley Periodicals, Inc. 相似文献
244.
Using a sample of 232 MBA alumni, we tested the impact of respondent age, gender, and their interaction on career progress outcomes (managerial level, number of promotions, and salary) and whether age‐ and gender‐type of contexts moderated these relationships. Women's salaries did not increase much with age, whereas men's salaries showed a marked increase with age. We also found a gender × job gender‐type effect on salary, such that women earned somewhat higher salaries in masculine‐typed jobs, while men earned considerably higher salaries in feminine‐typed jobs. In addition, we observed a three‐way interaction between gender, age, and age‐type of industry indicating that younger men received more promotions in old‐typed industries, while younger women received more promotions in young‐typed ones. Results are discussed in light of cognitive matching approaches and status characteristics theory. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
245.
Toan Nguyen Solveig Heide Lucie Guilbaud Stéphanie Valence Saskia Vande Perre Eléonore Blondiaux Boris Keren Geneviève Quenum-Miraillet Jean-Marie Jouannic Laurent Mandelbrot Olivier Picone Agnès Guet Vassilis Tsatsaris Mathieu Milh Nadine Girard Marie Vincent Mathilde Nizon Céline Poirsier Alexandre Vivanti Alexandra Benachi Vincent des Portes Laurent Guibaud Olivier Patat Myrtille Spentchian Lisa Frugère Delphine Héron Catherine Garel 《黑龙江环境通报》2023,43(6):746-755
246.
247.
248.
John A. Kronenberger Jill C. Gerberich Sarah W. Fitzpatrick E. Dale Broder Lisa M. Angeloni W. Chris Funk 《Conservation biology》2018,32(4):838-848
Human land use is fragmenting habitats worldwide and inhibiting dispersal among previously connected populations of organisms, often leading to inbreeding depression and reduced evolutionary potential in the face of rapid environmental change. To combat this augmentation of isolated populations with immigrants is sometimes used to facilitate demographic and genetic rescue. Augmentation with immigrants that are genetically and adaptively similar to the target population effectively increases population fitness, but if immigrants are very genetically or adaptively divergent, augmentation can lead to outbreeding depression. Despite well‐cited guidelines for the best practice selection of immigrant sources, often only highly divergent populations remain, and experimental tests of these riskier augmentation scenarios are essentially nonexistent. We conducted a mesocosm experiment with Trinidadian guppies (Poecilia reticulata) to test the multigenerational demographic and genetic effects of augmenting 2 target populations with 3 types of divergent immigrants. We found no evidence of demographic rescue, but we did observe genetic rescue in one population. Divergent immigrant treatments tended to maintain greater genetic diversity, abundance, and hybrid fitness than controls that received immigrants from the source used to seed the mesocosms. In the second population, divergent immigrants had a slightly negative effect in one treatment, and the benefits of augmentation were less apparent overall, likely because this population started with higher genetic diversity and a lower reproductive rate that limited genetic admixture. Our results add to a growing consensus that gene flow can increase population fitness even when immigrants are more highly divergent and may help reduce uncertainty about the use of augmentation in conservation. 相似文献
249.
250.
Lisa Ernoul 《国际发展与全球生态学杂志》2013,20(4):228-233
A perception study of the impacts that a new beach resort has, and will have, on the resident population in the northeast of Morocco was implemented during the construction phase of the resort. The residents have felt the impacts on local development, incomes, quality of life and the environment, and expressed their perception of how the opening of the new site will continue to impact their community. The study shows differences concerning the type of impact according to each professional sector. Despite the different perceptions, residents seem united in their overall concerns and fears about the how the new beach resort will impact the environment. 相似文献