全文获取类型
收费全文 | 73篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 1篇 |
废物处理 | 3篇 |
环保管理 | 8篇 |
综合类 | 26篇 |
基础理论 | 22篇 |
污染及防治 | 9篇 |
评价与监测 | 2篇 |
社会与环境 | 4篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2020年 | 1篇 |
2018年 | 2篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2012年 | 3篇 |
2011年 | 7篇 |
2010年 | 7篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1993年 | 4篇 |
1991年 | 2篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1967年 | 1篇 |
1964年 | 1篇 |
1958年 | 2篇 |
1955年 | 1篇 |
1952年 | 1篇 |
排序方式: 共有75条查询结果,搜索用时 15 毫秒
61.
Banitz T Wick LY Fetzer I Frank K Harms H Johst K 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2781-2788
Successful biodegradation of organic soil pollutants depends on their bioavailability to catabolically active microorganisms. In particular, environmental heterogeneities often limit bacterial access to pollutants. Experimental and modelling studies revealed that fungal networks can facilitate bacterial dispersal and may thereby improve pollutant bioavailability. Here, we investigate the influence of such bacterial dispersal networks on biodegradation performance under spatially heterogeneous abiotic conditions using a process-based simulation model. To match typical situations in polluted soils, two types of abiotic conditions are studied: heterogeneous bacterial dispersal conditions and heterogeneous initial resource distributions. The model predicts that networks facilitating bacterial dispersal can enhance biodegradation performance for a wide range of these conditions. Additionally, the time horizon over which this performance is assessed and the network’s spatial configuration are key factors determining the degree of biodegradation improvement. Our results support the idea of stimulating the establishment of fungal mycelia for enhanced bioremediation of polluted soils. 相似文献
62.
The term "barren hills" has been a keyword for land degradation in the uplands of Vietnam for over a decade. Nevertheless, the "barren" land is still not adequately ecologically characterized. In this work, we analyze land use-induced changes in vegetation and soil properties along a sequence of barren hills types formed on one physiotope. The study is undertaken in the Bac Kan province, one of the poorest upland regions where livestock plays an important role. A transition from an old-growth laurel forest to a sparse manmade grassland is characterized by a total of 177 species, rapid species turnover, and discrete dominants, and an overwhelming effect of disturbance history on both soil and vegetation patterning. Land degradation is most apparent in land use-induced maintenance of arrested successions, and the regeneration course is shifted towards drier formations. We hypothesize a conceptual model as an aid to understanding the process of early fallow differentiation in response to the patterned, fine-scale disturbances. The larger-scale implications of the observed trends in regeneration potentials deviation, and, in particular, the effect of water buffaloes in halting fallow successions, are discussed. 相似文献
63.
Rüdiger Riesch Ingo Schlupp Michael Tobler Martin Plath 《Behavioral ecology and sociobiology》2006,60(6):794-802
Cave animals are widely recognised as model organisms to study regressive evolutionary processes like the reduction of eyes. In this paper, we report on the regressive evolution of species discrimination in the cave molly, Poecilia mexicana, which, unlike other cave fishes, still has functional eyes. This allowed us to examine the response to both visual and non-visual cues involved in species discrimination. When surface-dwelling females were given a chance to associate with either a conspecific or a swordtail (Xiphophorus hellerii) female, they strongly preferred the conspecific female both when multiple cues and when solely visual cues were available to the female. No association preference was observed when only non-visual cues were provided. In contrast, cave-dwelling females showed no preference under all testing conditions, suggesting that species recognition mechanisms have been reduced. We discuss the role of species discrimination in relation to habitat differences. 相似文献
64.
PD Dr Ingo Kennerknecht Gotthold Barbi Michael Wolf Mahmoud Djalali Dieter Grab Rainer Terinde Walther Vogel 《黑龙江环境通报》1993,13(10):929-944
An increasing number of cytogenetic prenatal diagnoses are performed on chorionic villus samplings. The accuracy of this method is influenced by chromosomal mosaicism, mostly confined to direct preparation methods. Especially those investigators who have experienced false-negative and false-positive findings propagate the combined use of direct and culture methods. Yet large collaborative studies have shown that in approximately two-thirds of diagnostic cases only one procedure is applied. Moreover, the accuracy of a cytogenetic investigation depends not only on the ontogenetic origin of the tissues investigated, but also on interacting factors such as the ‘a priori risk’ and the ‘predictive value of a cytogenetic finding’. On this basis a differentiated prenatal diagnostic procedure is discussed, including either sole short-term culture (STC), combined STC and long-term culture (LTC), primary amniocentesis (AC), or primary percutaneous umbilical blood sampling (PUBS). The predictive value of the cytogenetic diagnosis from CVS varies significantly dependent on the a priori risk of a chromosome aberration and, in the case of an abnormal karyotype, on the specific chromosome involved. A non-mosaic and ‘non-lethal’ trisomy detected in STC is highly representative of the embryo/fetus, but there are exceptions of limited predictive value, e.g., trisomy 18. Guided by the strategy of an optional follow-up by LTC, AC, or PUBS in 1317 successive CV samplings, we are not aware of a false-negative diagnosis, but probably had one false-positive diagnosis: 47,XXY after STC; 46,XY after LTC. When referring to the rate of fetuses with an unbalanced karyotype expected in the different indication groups, a relative increase of false-positive findings in the very-low-risk group (maternal age ⩽35 years of age) and of false-negative findings in the very-high-risk group (abnormal ultrasonographic findings) of pregnant women when only performing CVS becomes obvious. Because of this dilemma, AC or—especially in the latter group—PUBS might be primarily offered to these indication groups instead of CVS. 相似文献
65.
Prior to a prospective application of amniotic fluid (AF) cell filtration to early amniocentesis, we tested the technique on a surplus from mid-trimester samples. By using the same sample size of 5 ml in experiments with a filter and in routine diagnostic procedures (control), we evaluated an optimal filter system. The prolonged culture time of filtered cells and the reduced number of clones are most probably due to mechanical stress (filtration pressure), whereas loss of the cells by adhesion to the filter system, and an AF-free culture medium (growth factors) are suggested to be less important. The AF cells are very sensitive to mechanical stress. Slow filtration (⩽3 ml AF/min) through filters with a high porosity and the largest possible pore size should be preferred. A mixed cellulose ester filter membrane with a pore size of 5·0 μm proved to be the most efficient, allowing harvest of the filtered cells after only a slight prolongation of the culture time (+2·4 days) compared with unfiltered aliquots. A filter set with a bypass connected by three-way taps allows cell filtration during either aspiration or reinjection of the AF. Cell filtration after amniocentesis and consecutive reverse flushing of the membrane with the appropriate amount of culture medium proved to be the best with regard to easy handling and reducing the risk of bacterial contamination. 相似文献
66.
Hartmut Koehler Tobias Frische Ingo Dobner Peter Behrend Maike Schaefer Heidi Taubner Bernd Jastorff Jürgen Warrelmann Ulrich Walter 《Environmental Sciences Europe》2001,13(5):291-300
Results of a field experiment (please refer to Warrelmann et al. 2000a) document TNT-degradation and regeneration after the establishment of a phytoremediation. Various approaches are included in a complex monitoring system, which are conducted in the field (nitroaromatics in soil, seepage water, and plants; soil fauna; soil fungi; decomposition) as well as in the lab (a battery of 6 biotests). The data document a high heterogeneity of the TNT-contamination, a rapid initial decrease and a mediocre displacement of nitroaromatics in plants and seepage water. The initial rapid transformation of TNT to aminodinitrotoluenes ceases significantly after 3 months. Results of the biotest battery allow a sophisticated assessment of soil toxicity; the results from the soil ecological field investigations make the long-term effects of TNT-contamination likely. In a third part of the series of articles, a synopsis and judgement of the project will be delivered. 相似文献
67.
Ulrich Heink Robert Bartz Ingo Kowarik 《Journal of Agricultural and Environmental Ethics》2012,25(1):3-17
In the discussion about consequences of the release of genetically modified (GM) crops, the meaning of the term “environmental
damage” is difficult to pin down. We discuss some established concepts and criteria for understanding and evaluating such
damages. Focusing on the concepts of familiarity, biological integrity, and ecosystem health, we argue that, for the most
part, these concepts are highly ambiguous. While environmental damage is mostly understood as significant adverse effects
on conservation resources, these concepts may not relate directly to effects on tangible natural resources but rather to parameters
of land use or ecological processes (e.g., the concept of biological integrity). We stress the importance of disclosing the
normative assumptions underlying damage concepts and procedures for the evaluation of damages by GM crops. A conceptualization
of environmental damage should precede its operationalization. We recommend an unambiguous definition for damage developed
earlier and recommend that evaluation criteria be based on this. However, a general damage definition cannot replace case-specific
operationalization of damage, which remains an important future challenge. 相似文献
68.
知识网络是由创造、转移、吸收和应用知识的行为主体在知识的传播与交流过程中彼此联结而形成的网络结构。以国际ISI和国内VIP数据库中2000~2009年发表于生物技术领域的合著论文作者信息统计数据为数据源,基于社会网络分析的理论和方法,从国际和国内省级层面运用UCINET和Pajek软件分析知识网络的空间极化和扩散规律。总体上看网络仍处于量的扩张期,网络的稳健性正在逐步提高,网络结构开始向成熟型转变。国际层面上看,知识网络的空间极化现象明显。国内层面上看,知识网络由等级结构向扁平结构转变,空间上相应地经历了由一极向多核再向多中心发展的过程。依据知识网络空间分布特征,将知识交流区域分为知识集聚区、知识门户区、知识途径区及知识边缘区四大类型,并对我国的技术创新政策提出对策建议 相似文献
69.
70.