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   228篇
  免费   2篇
  国内免费   1篇
安全科学   8篇
废物处理   11篇
环保管理   20篇
综合类   20篇
基础理论   52篇
污染及防治   77篇
评价与监测   24篇
社会与环境   19篇
  2023年   3篇
  2022年   4篇
  2021年   5篇
  2020年   6篇
  2019年   2篇
  2018年   5篇
  2017年   8篇
  2016年   17篇
  2015年   8篇
  2014年   10篇
  2013年   20篇
  2012年   11篇
  2011年   17篇
  2010年   10篇
  2009年   11篇
  2008年   12篇
  2007年   14篇
  2006年   8篇
  2005年   8篇
  2004年   10篇
  2003年   9篇
  2002年   10篇
  2001年   1篇
  2000年   3篇
  1999年   2篇
  1998年   2篇
  1997年   1篇
  1996年   4篇
  1995年   3篇
  1992年   1篇
  1988年   1篇
  1977年   1篇
  1970年   1篇
  1963年   1篇
  1956年   1篇
  1955年   1篇
排序方式: 共有231条查询结果,搜索用时 156 毫秒
101.
In this study, we investigated the toxic effects of water-soluble elements from a contaminated soil via gavage in a single dose, simulating a geophagy event. The contaminated soil was collected in a field located in an industrial complex, and the control soil was collected in a reference area. Metabolic and behavioral parameters in Wistar male rats were measured after 24 and 96 h of gavage. After 96 h, the major organs were weighed, blood was collected to check hematological parameters, the bone marrow was taken for the micronucleus test, and the liver was used for evaluating the total antioxidant capacity, lipoperoxidation and protein carbonylation. Animals exposed to contaminated soil presented a few significant alterations by comparison with control animals: TBARS and protein carbonyl levels increased, the relative weight of the kidneys increased, metabolic parameters (body weight gain, food intake, water consumption, urine and feces production) depressed and there was behavioral alteration. These findings suggest that soils impacted by atmospheric contaminants can affect the organism physiological status jeopardizing the health of populations living in industrial areas. Finally, this study reassures that ingestion of potentially contaminated soils, even for short periods of time, can cause health risks.  相似文献   
102.
103.
This study examined the adverse effects of N,N,N′,N′-tetramethylethylenediamine (TEMED) on electric eel (Electrophorus electricus) acetylcholinesterase (AChE) and human serum butyrylcholinesterase (BChE). Data show that TEMED inhibited AChE in electric eel as well as human serum BChE. Kinetic studies indicated that the inhibition produced by TEMED in both sources was of mixed type, i.e. Km increased and V max decreased in a concentration-dependent manner. KI (constant of ChE–substrate–TEMED complex into ChE–substrate complex and TEMED) was estimated to be 0.674 mM for electric eel and 0.024 mM for human serum BChE. The γKm (dissociation constant of ChE–substrate–TEMED complex into ChE–TEMED complex and substrate) was 0.083 and 0.2 mM for electric eel AChE and human serum BChE, respectively. The IC50 for electric eel and for human serum ChE was 1.57 and 0.043 mM, respectively. The present results suggest that TEMED produced adverse effects on electric eel and human serum via inhibition of ChE.  相似文献   
104.
105.
Behavioral Ecology and Sociobiology - The killing of young by unrelated males is widespread in the animal kingdom. In short-lived small rodents, females can mate immediately after delivery...  相似文献   
106.
Concentration levels, seasonal variation and winter/summer ratios of 11 polycyclic aromatic hydrocarbons (PAHs) in the TSP of Las Palmas de Gran Canaria city were determined. The study area is under the influence of heavy traffic (80000 vehicles/day). Pyr/BaA, Pyr/Flt, B(ghi)P/I(cd)P and B(b+k)F/B(ghi)P ratios were calculated; the values of these two last suggest a strong influence of diesel fuel burning. Levels of TSP and TSP-bound PAHs were also established. The hazard potential of PAHs in terms of carcinogenicity of BaP is acceptable. Potential risk on the basis of TEFs is also studied.  相似文献   
107.
Silica gel surface has been modified in two reaction steps: (i) the silylating agent 3-mercaptopropyltrimetoxysilane was firstly immobilized to give a surface Sil-SH and (ii) this precursor incorporated an ethylene sulfide molecule to obtain the surface denoted Sil-SSH. This material was characterized by elemental analysis, IR spectroscopy, thermogravimetry, solid state 13C and 29Si NMR, and surface area measurement. These materials were employed as adsorbents for divalent heavy cations from aqueous solutions at room temperature and the isotherms were adjusted to a modified Langmuir equation. The maxima number of moles adsorbed were 1.0, 1.5, 1.6, 2.2, 2.4 and 3.3 mmol g(-1) for Co, Cu, Ni, Cd, Pb, and Hg, respectively.  相似文献   
108.
In addition to encoding referential information and information about the sender’s motivation, mammalian alarm calls may encode information about other attributes of the sender, providing the potential for recognition among kin, mates, and neighbors. Here, we examined 96 speckled ground squirrels (Spermophilus suslicus), 100 yellow ground squirrels (Spermophilus fulvus) and 85 yellow-bellied marmots (Marmota flaviventris) to determine whether their alarm calls differed between species in their ability to encode information about the caller’s sex, age, and identity. Alarm calls were elicited by approaching individually identified animals in live-traps. We assume this experimental design modeled a naturally occurring predatory event, when receivers should acquire information about attributes of a caller from a single bout of alarm calls. In each species, variation that allows identification of the caller’s identity was greater than variation allowing identification of age or sex. We discuss these results in relation to each species’ biology and sociality.  相似文献   
109.
Society needs to adapt in order to provide the wealth that an increasing part of the world population is getting used to. We are on a track to ecological and resource collapse if actions are not taken soon. Technology will have to play a key role in the process of changing industrial society. But innovation has to be embedded in social and organizational innovation. We need sociotechnical change. Environmentally conscious design has been practiced in engineering design for more than a decade. Its merits are sometimes blamed as futile, as the world has not witnessed a significant contribution to the solution of the larger (global) problems. This paper first sketches a scheme of the various levels of technological change, ranging from: (1) incremental optimizations of single artifacts, to (2) major change of artifacts, (3) systems change, and (4) technological transitions (involving changes in production and consumption). It outlines the stakeholders involved in these types of innovations and the parties that could orchestrate the innovation process. In this paper, It is argued that the most encompassing level of technological innovation, the level of transition, is crucial for achieving long-term sustainable development, as it has the largest potential for improvement. However, transition is not very well manageable. The paper contains a review of the literature regarding the occurrence of technological transitions. After a transition has occurred, the new system is often not efficient. Its gains in terms of diminished resource consumption or pollution have to be enlarged by less encompassing innovation strategies, such as systems innovations and product optimization. Transitions for sustainable development are often impossible, as the new systems have to compete with fully developed and optimized systems that have far advanced at the learning curve, i.e., are optimized by various systems and incremental innovations. Less encompassing levels of innovation, even those that aim at more sustainability, can counteract transitions that have more potential for sustainable development by improving the competing (unsustainable) technology. The paper will give several examples of this dilemma and some guidelines for developing government policies as well as corporate strategies. On the policy level, it is argued that it is especially important to develop (scope for) market niches for new sustainable systems and products as they create scope for experiments that could lead to transitions.
Karel F. MulderEmail:
  相似文献   
110.

Converting raw biomass into valuable products protects the environment, improves economics, and helps tackle climate change by cutting resource demand and waste production. Thermochemical treatment is a common method for producing biochars, hydrochars and torreficates from biomass and organic wastes, which can also generate dioxins and furans and consequently limit the use of thermochemically converted chars. Here we review the presence of dioxins and furans in chars produced by hydrothermal carbonization, torrefaction, and pyrolysis processes under the influence of temperature, residence time, heating rate, pressure, and feedstock type. Dioxins and furans were mostly below 20 ng total toxic equivalence per kilogram (TEQ kg−1), with the highest level of 113 ng TEQ kg−1 found in over 100 samples of different char types. The most toxic products were hydrochars produced from sewage sludge. Processing temperature and feedstock type were key factors resulting in high dioxin levels in chars, and care should be taken when producing chars at temperatures up to 300 °C or using feedstocks previously contaminated with dioxins or preservatives.

  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