首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   305篇
  免费   11篇
  国内免费   6篇
安全科学   8篇
废物处理   22篇
环保管理   38篇
综合类   81篇
基础理论   60篇
污染及防治   83篇
评价与监测   15篇
社会与环境   10篇
灾害及防治   5篇
  2023年   5篇
  2022年   13篇
  2021年   21篇
  2020年   11篇
  2019年   11篇
  2018年   20篇
  2017年   10篇
  2016年   19篇
  2015年   7篇
  2014年   13篇
  2013年   24篇
  2012年   16篇
  2011年   27篇
  2010年   13篇
  2009年   17篇
  2008年   12篇
  2007年   9篇
  2006年   12篇
  2005年   5篇
  2004年   7篇
  2003年   11篇
  2002年   11篇
  2001年   7篇
  2000年   3篇
  1998年   2篇
  1997年   1篇
  1994年   4篇
  1993年   1篇
  1992年   1篇
  1990年   2篇
  1988年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1979年   1篇
排序方式: 共有322条查询结果,搜索用时 31 毫秒
101.
102.
Amniotic fluids were obtained from 19 mothers who had previously given birth to a child with cystic fibrosis. Measurement of methylumbelliferyl guanidinobenzoate (MUGB) reactive proteases suggested that all 19 would have unaffected babies. Amongst the first 10 cases to come to term there were 5 infants with cystic fibrosis. It is concluded that MUGB protease titration is not suitable for the early prenatal diagnosis of cystic fibrosis.  相似文献   
103.
A submicroscopic genomic duplication in Xq22.2 that contains the entire proteolipid protein 1 gene (PLP1) is responsible for the majority of Pelizaeus–Merzbacher disease (PMD) patients. We previously developed an interphase FISH assay to screen for PLP1 duplications in PMD patients using peripheral blood and lymphoblastoid cell lines. This assay has been utilized as a clinical diagnostic test in our cytogenetics laboratory. To expand usage of the interphase FISH assay to prenatal diagnosis of PLP1 duplications, we examined three PMD families with PLP1 duplications utilizing aminiotic fluid samples. In two families the FISH assay revealed fetuses with PLP1 duplications, whereas the other fetus showed a normal copy number of PLP1. Haplotype analyses, as well as an additional FISH analysis using postnatal blood samples, confirmed the results of the prenatal analyses. Our study demonstrates utility of the interphase FISH assay in the prenatal diagnosis of PLP1 duplications in PMD. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
104.
In this study, we investigated team‐based community service projects as action learning initiatives designed to facilitate two learning outcomes: community learning (knowledge of social, cultural, or economic issues) and personal learning (self‐awareness of managerial attitudes and abilities). We developed hypotheses to predict critical input conditions for action learning that promote community and personal learning. We tested these hypotheses with data collected from 381 MBA students and their team leaders who participated in a variety of community service projects. Results demonstrated that design conditions (task characteristics, social interactions, and affective responses) influenced community and personal learning differently. We supplemented survey results with interview and observational data from a subset of participants and conclude with a discussion of the theoretical implications for action learning and practical recommendations for designing community service programs. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
105.
106.
Environmental Science and Pollution Research - Coal extraction and processing generate environmental contamination, which has several negative impacts on human health. Hematological and biochemical...  相似文献   
107.
Like the rest of the world, African countries are reeling from the health, economic and social effects of COVID-19. The continent’s governments have responded by imposing rigorous lockdowns to limit the spread of the virus. The various lockdown measures are undermining food security, because stay at home orders have among others, threatened food production for a continent that relies heavily on agriculture as the bedrock of the economy. This article draws on quantitative data collected by the GeoPoll, and, from these data, assesses the effect of concern about the local spread and economic impact of COVID-19 on food worries. Qualitative data comprising 12 countries south of the Sahara reveal that lockdowns have created anxiety over food security as a health, economic and human rights/well-being issue. By applying a probit model, we find that concern about the local spread of COVID-19 and economic impact of the virus increases the probability of food worries. Governments have responded with various efforts to support the neediest. By evaluating the various policies rolled out we advocate for a feminist economics approach that necessitates greater use of data analytics to predict the likely impacts of intended regulatory relief responses during the recovery process and post-COVID-19.  相似文献   
108.
SMPD4 loss is a rare neurodevelopmental disorder that leads to severe mental and physical disability and early death in infancy. Most cases of this genetic condition have been diagnosed postnatally. This article focuses on the prenatal findings of affected fetuses. The phenotypes can include growth restriction, arthrogryposis (clenched hands, foot deformity), as well as cerebral abnormalities (simplified gyral pattern/lissencephaly, cerebellar hypoplasia, corpus callosum deformity). SMPD4 loss is detectable via exome sequencing. Here, two fetuses displayed a homozygotic pathogen variant in the SMPD4 gene, encoding for the enzyme Sphingomyelinase-4. Both parents were heterozygous carriers of the pathogenic variant. On detection of the above mentioned signs exome sequencing is indicated, with focus on the SMPD4 gene.  相似文献   
109.
One commonly accepted mechanism for biological invasions is that species, after introduction to a new region, leave behind their natural enemies and therefore increase in distribution and abundance. However, which enemies are escaped remains unclear. Escape from specialist invertebrate herbivores has been examined in detail, but despite the profound effects of generalist herbivores in natural communities their potential to control invasive species is poorly understood. We carried out parallel laboratory feeding bioassays with generalist invertebrate herbivores from the native (Europe) and from the introduced (North America) range using native and nonnative tetraploid populations of the invasive spotted knapweed, Centaurea stoebe. We found that the growth of North American generalist herbivores was far lower when feeding on C. stoebe than the growth of European generalists. In contrast, North American and European generalists grew equally well on European and North American tetraploid C. stoebe plants, lending no support for an evolutionary change in resistance of North American tetraploid C. stoebe populations against generalist herbivores. These results suggest that biogeographical differences in the response of generalist herbivores to novel plant species have the potential to affect plant invasions.  相似文献   
110.
Jellyfish are increasingly topical within studies of marine food webs. Stable isotope analysis represents a valuable technique to unravel the complex trophic role of these long-overlooked species. In other taxa, sample preservation has been shown to alter the isotopic values of species under consideration, potentially leading to misinterpretation of trophic ecology. To identify potential preservation effects in jellyfish, we collected Aurelia aurita from Strangford Lough (54o22′44.73″N, 5o32′53.44″W) during May 2009 and processed them using three different methods prior to isotopic analysis (unpreserved, frozen and preserved in ethanol). A distinct preservation effect was found on δ15N values: furthermore, preservation also influenced the positive allometric relationship between individual size and δ15N values. Conversely, δ13C values remained consistent between the three preservation methods, conflicting with previous findings for other invertebrate, fish and mammalian species. These findings have implications for incorporation of jellyfish into marine food webs and remote sampling regimes where preservation of samples is unavoidable.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号