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   8篇
  免费   1篇
  国内免费   1篇
环保管理   1篇
综合类   4篇
基础理论   3篇
评价与监测   1篇
社会与环境   1篇
  2023年   1篇
  2017年   1篇
  2014年   1篇
  2011年   1篇
  2009年   2篇
  2008年   1篇
  2001年   1篇
  1989年   1篇
  1981年   1篇
排序方式: 共有10条查询结果,搜索用时 31 毫秒
1
1.
We present a family who sought prenatal diagnosis in order to bear a healthy child to serve as an HLA–identical bone marrow donor for their son affected with Wiskott–Aldrich syndrome. They intended to abort HLA-incompatible fetuses who would have been unsuitable bone marrow donors. This case led us to conclude that prenatal diagnosis should not be used to benefit a third party or facilitate the conception or abortion of a fetus for the purpose of generating an organ for transplantation. The limits of parental autonomy and physician responsibility are discussed.  相似文献   
2.
The role that genetic and environmental factors play in triggering neural tube defects in the mouse mutant curly-tail (ct) were investigated by transplanting curly-tail blastocysts into the uterus of either curly-tail females or females of an unrelated A strain with a low natural incidence of abnormalities of the neural tube. The percentages of fetuses with neural tube defects were found to be similar in both groups. These results show that in curly-tail mice exencephaly and spina bifida are manifested independently of the maternal environment.  相似文献   
3.
综述了影响肾移植患者心理健康的原因以及社会支持与心理健康的相关性,并探讨通过社会支持提高肾移植患者心理健康水平的途径.从而提示护理工作者在工作中应尽可能调动肾移植患者本人、家庭成员及社会的主观能动性,以提高肾移植患者的心理健康水平.  相似文献   
4.
Advancements in the field of reintroduction biology are needed, but understanding of how to effectively conduct translocations, particularly with snakes, is lacking. We conducted a systematic review of snake translocation studies to identify potential tactics for reducing postrelease effects. We included studies on intentional, human-mediated, wild–wild, or captive–wild translocations to any location, regardless of motive or number of snakes translocated. Only studies that presented results for at least 1 of 4 outcomes (movement behavior, site fidelity, survival, or population establishment) were included. We systematically searched 4 databases for published studies and used 5 methods to search the gray literature. Our search and screening criteria yielded 121 data sources, representing 130 translocation cases. We quantified the association between 15 translocation tactics and short-term translocation outcomes by calculating odds ratios and used forest plots to display results. Snake translocations involved 47 species (from mainly 2 families), and most were motivated by research, were monitored for at least 6 months, occurred in North America, and took place from the 1990s onward. The odds of a positive snake translocation outcome were highest with release of captive reared or juvenile snakes, release of social groups together, delayed release, provision of environmental enrichment or social housing before release, or minimization of distance translocated. The odds of a positive outcome were lowest when snakes were released early in their active season. Our results do not demonstrate causation, but outcomes of snake translocation were associated with 8 tactics (4 of which were strongly correlated). In addition to targeted comparative studies, we recommend practitioners consider the possible influence of these tactics when planning snake translocations.  相似文献   
5.
A sequential extraction procedure was used to study localization of heavy metals in thalli of the lichen Hypogymnia physodes (L.) Nyl. growing under conditions of chronic aerotechnogenic pollution in the Middle Urals. Trends in the seasonal dynamics of metal contents in the thalli were revealed. The dynamics of metal accumulation was also studied in the thalli brought to the polluted zone from the background environment. After one year, the extra-and intercellular contents of most metals in these transplants approached those in the aboriginal thalli and in some cases (intracellular content of cadmium) exceeded them.  相似文献   
6.
移殖“标准化”背角无齿蚌监测五里湖重金属污染   总被引:2,自引:0,他引:2       下载免费PDF全文
移殖生物因子相同、遗传质量稳定和污染本底值低的“标准化”背角无齿蚌至太湖五里湖,并以仍养殖在未受污染的中国水产科学研究院淡水渔业研究中心南泉基地的同批蚌作为对照,每3个月回收蚌样,应用电感耦合等离子质谱仪(ICP-MS)研究了重金属Al、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mo、Ag、Cd、Ba、Tl和Pb的含量变化.结果表明,“标准化”背角无齿蚌对重金属的积累与特定的季节/时间密切相关,在夏季的含量明显低于春季.移殖五里湖3个月蚌样中Mo和Tl的含量显著高于相应的对照组(P<0.05),而前者Ba的含量显著低于后者(P<0.05).移殖五里湖6个月蚌样中As的含量显著低于对照组(P<0.05).综合重金属污染指数(MPI)和我国及国际上的相关限量标准评价显示,五里湖和南泉基地水体中重金属的含量处于相同水平,重金属污染均不明显.  相似文献   
7.
池塘养殖及野外移殖三角帆蚌元素积累的差异   总被引:1,自引:0,他引:1  
以从湖北公安养殖池塘移殖到三峡库区童庄河自然水域试养1 a和仍在原池塘养殖的同1批次三角帆蚌(Hyriopsis cumingii)为对象,用电感耦合等离子质谱仪测定了2地三角帆蚌软组织中K、Mg、Ca、Fe、Zn、Mn、Cu、As、Al、Cr、Ni、Se、Mo、Ag、Cd、Ti、Pb 17种元素的含量.结果表明,虽然2水域中三角帆蚌软组织内各元素含量间的高低差异具有相似的趋势,体现了三角帆蚌对元素积累的特征,但自然水域蚌中有9种元素的水平高于养殖水域,提示不同栖息环境背景对元素的积累水平能产生重要影响.自然水域单个三角帆蚌体内软组织中元素积累的平均负荷量普遍高于养殖池塘的个体,提示三角帆蚌具有显著的元素吸收、净化能力.本研究为今后通过大规模移殖双壳贝类来监测自然水域元素污染提供了依据.  相似文献   
8.
Lichens explants and airborne particulates were analysed for Cr, Zn, Cd, Pb, Ni, Fe, Mn and Cu content in a rural site in the province of Vercelli (Piedmont, N. Italy). Thalliof the fruticose lichen Pseudevernia furfuracea were collected from an uncontaminated area and exposed for one yearusing two different techniques. Particulates were collected using a continuously operating particulate sampler set up nearthe lichens explanted throughout the experiment survey.The results confirm both the importance of assessing contamination in rural areas corroborated by the analysis of the presence of the heavy metals in particulates in relationto the main wind directions and the validity of this lichen asbiomonitor of airborne metal pollution, although meaningfuldifferences were pointed out between the two different techniques of exposure. The significant correlation between most of the metals accumulated by lichens and the metal air concentrations shows a good evidence of their ability to represent atmospheric contamination.  相似文献   
9.
Local and scientific knowledge, when adequately and properly integrated, produces enormous benefits for natural resource management in comparison to a single knowledge system being used. Adequate and proper integration has major constraints that include ineffective use of the integrated knowledge, thoroughly inclusive processes, and true public participation. A six-stage framework is developed using the results and conclusions of two case studies regarding sustainable management of eroding mangrove-dominated muddy coasts in Vam Ray, Hon Dat district, Kien Giang Province, Vietnam. The framework does not stop with the creation of integrated knowledge, but should undergo a longer process. The new knowledge developed in this framework is the understanding gained and lessons learnt during the testing of products of multiple knowledge systems in a local context rather than products of integrated knowledge systems themselves. The Vam Ray framework promotes a high level of participation, effective use of products of multiple knowledge systems, maximum integration of local and scientific knowledge, local ownership, and sustainability. Therefore, the Vam Ray framework adds a new dimension to the literature in relation to integration of local and scientific knowledge in natural resource management.  相似文献   
10.
水热条件与土壤性质对农田土壤硝化作用的影响   总被引:13,自引:3,他引:10  
水热条件、土壤性质和耕作管理影响了土壤的硝化作用从而影响农田氮素循环和平衡.本试验选择中国东部3个气候带上的主要农田土壤:中温带黑龙江海伦的黑土、暖温带河南封丘的潮土和中亚热带江西鹰潭的红壤,在上述3个地点的生态试验站建立土壤置换试验,对比研究不同水热条件和土壤类型对玉米单作系统中土壤硝化作用的交互影响.2006~2007年的试验结果表明,在玉米抽雄期,从海伦到鹰潭(月均温由22.3℃上升到26.8℃,月降水由100.8 mm增加到199.6 mm),3种土壤的硝化作用强度均随着月均温和月降水的增加而下降,黑土、潮土和红壤分别下降了64.2%~67.2%、 52.1%~52.5%和41.7%~75.2%,土壤的硝化作用强度与气温(r=-0.354,p<0.01)和降水(r=-0.290,p<0.01)均呈极显著负相关.土壤类型也显著影响了土壤硝化细菌的数量和硝化强度,硝化细菌数和硝化强度的大小顺序为:潮土> 黑土> 红壤.土壤pH对土壤硝化强度有显著影响,其相关系数r=0.551(p<0.01).总体上,在玉米抽雄期,区域水热状况及土壤类型、施肥均影响了土壤的硝化强度,水热×土壤类型、水热×施肥、土壤类型×施肥、水热×土壤类型×施肥等对硝化强度有着极显著的交互作用.  相似文献   
1
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