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   134篇
  免费   1篇
安全科学   8篇
废物处理   1篇
环保管理   9篇
综合类   40篇
基础理论   19篇
污染及防治   37篇
评价与监测   11篇
社会与环境   8篇
灾害及防治   2篇
  2021年   3篇
  2019年   3篇
  2018年   3篇
  2017年   4篇
  2016年   6篇
  2014年   6篇
  2013年   9篇
  2011年   5篇
  2010年   7篇
  2009年   8篇
  2008年   6篇
  2007年   5篇
  2006年   2篇
  2004年   7篇
  2003年   2篇
  2002年   2篇
  2000年   2篇
  1999年   3篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1986年   1篇
  1985年   1篇
  1983年   1篇
  1982年   1篇
  1980年   3篇
  1978年   1篇
  1976年   2篇
  1974年   1篇
  1972年   1篇
  1971年   2篇
  1969年   1篇
  1968年   1篇
  1967年   2篇
  1966年   2篇
  1964年   1篇
  1962年   2篇
  1961年   3篇
  1960年   1篇
  1959年   1篇
  1958年   1篇
  1957年   1篇
  1954年   4篇
  1932年   1篇
  1929年   1篇
  1923年   1篇
  1921年   1篇
排序方式: 共有135条查询结果,搜索用时 31 毫秒
81.
82.
Large-scale contaminated sites with multiple contaminants in the groundwater present a challenge to risk assessment and remediation. Attenuation reactions take place in the subsurface and act to contain contaminants, but must be thoroughly investigated on a site-specific basis. Field data from monitoring wells at a contaminated industrial site in Bitterfeld, Germany, are presented and analyzed for evidence of the prevalent biodegradation reactions. The groundwater in the Tertiary aquifer is contaminated with large quantities of chlorinated aliphatic compounds, in addition to chlorobenzenes and BTEX. In this strictly anaerobic environment, geochemical indications for several microbial processes were found, including methanogenesis, sulfate and iron reduction as well as reductive dechlorination of the chlorinated hydrocarbons. Direct evidence for the latter degradation reaction was observed along the flowpath due to the appearance of intermediates and an increase in the degree of dechlorination.  相似文献   
83.
For wide-area atmospheric monitoring, krypton-85 is the best indicator for clandestine plutonium separations. The detection and false alarm rates were determined from weekly samples at five different distances from the Karlsruhe reprocessing plant between 1985 and 1988. The detection rate for the separation of 4 kg of plutonium per week was found to be as high as 80-90% at a distance of less than 1 km, 70% at 5 km, 40% at 39 km, and 15% at 130 km. At distances up to 40 km, the false alarm rate is less than 3.5%. On average, the fuel released 28 TBq krypton-85 per kg plutonium. For weapons-grade plutonium, the krypton signal would be lower by a factor of 2. Hence, the given percentages correspond to the detection probabilities for the separation of a significant quantity (8 kg) of plutonium per weekly sample under the specific meteorological conditions of the WAK. The minimum separation rates that could have been detected are 2 gram of weapons-grade plutonium per week at a distance of less than 1 km, 40 g/week at 5 km, 200 g/week at 39 km, and 1000 g/week at 130 km.  相似文献   
84.
The separation of organic coatings from fibrous substrates is a key problem in recycling processes. This problem applies to carpets, technical textiles and automotive interior components. This paper reports about results of laboratory studies involving the application of high-speed liquid jets to solve this problem. Results from high-speed video images are used to qualify the principal erosion process. It is shown that the coating material is first ground by the jet; the generated erosion debris is then pushed through the permeable fibrous fabric of the substrate. It is also found that threshold conditions exist for the coating grinding process and for the debris transportation. These threshold conditions depend on target composition and process parameters. A phenomenological separation model is introduced. The influence of key process parameters, namely jet velocity, exposure time, stand-off distance and impact angle, is also investigated. It is found that high-speed liquid jets are suitable tools for separating organic coatings completely and selectively from fibrous substrates. Recommendations on how to optimise the erosion process are derived from the results.  相似文献   
85.
Weiss P  Lorbeer G  Scharf S 《Chemosphere》2000,40(9-11):1159-1171
Spruce needles and humus layer of 25 remote forest sites spread all over Austria were investigated for their concentrations of PCDD/F, PCB, HCH, HCB, PCP, DDX and PAH. Influences of the sites' location on the detected concentrations have been identified: The north of Austria was characterised by a comparably higher overall pollutant load. In addition, altitudinal aspects were addressed. Between several compounds significant positive correlations have been identified, which were more pronounced for compounds with a stronger causal relationship. Pattern analyses allowed to identify--even for the remote sites--differences between the relative PCDD/F, HCH, DDX and PAH patterns of the sites. Partly, these different patterns were related to significantly higher or lower corresponding absolute concentrations of the sites.  相似文献   
86.
The use of the xenon isotopes for detection of nuclear explosions is of great interest for monitoring compliance with the comprehensive nuclear-test-ban treaty (CTBT). Recently, the automated radioxenon sampler-analyzer (ARSA) was tested at the Institute for Atmospheric Radioactivity (IAR) in Freiburg, Germany to ascertain its use for the CTBT by comparing its results to laboratory-based analyses, determining its detection sensitivity and analyzing its results in light of historical xenon isotope levels and known reactor operations in the area. Xe-133 was detected nearly every day throughout the test at activity concentrations ranging between approximately 0.1 mBq/m3 to as high as 120 mBq/m3. Xe-133m and 135Xe were also detected occasionally during the test at concentrations of less than 1 to a few mBq/m3.  相似文献   
87.
The SAFIRA in situ pilot plant in Bitterfeld, Saxonia-Anhalt, Germany, currently serves as the test site for eight different in situ approaches to remediate anoxic chlorobenzene (CB)-contaminated ground water. Two reactors, both filled with originallignite-containing aquifer material, are designed for themicrobiological in situ remediation of the ground water bythe indigenous microbial consortia. In this study, thehydrogeological, chemical and microbiological conditions of theinflowing ground water and reactor filling material are presented,in order to establish the scientific basis for the start of thebioremediation process itself. The reactors were put intooperation in June 1999. In the following, inflow CB concentrationsin the ground water varied between 22 and 33 mg L-1; achemical steady state for CB in both reactors was reachedafter 210 till 260 days operation time. The sediments werecolonized by high numbers of aerobic, iron-reducing anddenitrifying bacteria, as determined after 244 and 285 days ofoperation time. Furthermore, aerobic CB-degrading bacteria weredetected in all reactor zones. Comparative sequence analysis of16S rDNA gene clone libraries suggest the dominance of Proteobacteria (Comamonadaceae, Alcaligenaceae, Gallionella group, Acidithiobacillus) and members of theclass of low G+C gram-positive bacteria in the reactorsediments. In the inflowing ground water, sequences withphylogenetic affiliation to sulfate-reducing bacteria andsequences not affiliated with the known phyla of Bacteria, were found.  相似文献   
88.
Thomas G. Weiss 《Disasters》1997,21(2):95-117
'Military-civilian humanitarianism'— or the coming together of military forces and civilian aid agencies to deal with the human suffering from complex emergencies — has numerous forms, but disenchantment has resulted from the Somalia and Bosnia syndromes. There is little political will at present, but evidence from the immediate post-Cold War era suggests how multilateral military operations could expand or contract in future to the benefit or peril of war victims. Partly a literature review but more importantly a framework for interpreting recent publications, this essay seeks to move beyond exchanging assertions. There is a contextualisation of recent literature; a definition of military-civilian humanitarianism; a discussion of possible military contributions to humanitarian action; a framework to assess the effectiveness of military-civilian humanitarianism; and a preliminary analysis of experience from northern Iraq, Somalia, Bosnia, Rwanda and Haiti. Caveat lector : At this point in time, there are still 'more questions than answers'.  相似文献   
89.
A peat core from Lindow bog near Manchester, England, was precisely cut into 2 cm slices to provide a high-resolution reconstruction of atmospheric Pb deposition. Radiocarbon and (210)Pb age dates show that the peat core represents the period ca. 2000 BC to AD 1800. Eleven radiocarbon age dates of bulk peat samples reveal a linear age-depth relationship with an average temporal resolution of 18.5 years per cm, or 37 years per sample. Using the Pb/Ti ratio to calculate the rates of anthropogenic, atmospheric Pb deposition, the profile reveals Pb contamination first appearing in peat samples dating from ca. 900 BC which clearly pre-date Roman mining activities. Using TIMS, MC-ICP-MS, and SF-ICP-MS to measure the isotopic composition of Pb, the (208)Pb/(206)Pb and (206)Pb/(207)Pb data indicate that English ores were the predominant sources during the pre-Roman, Roman, and Medieval Periods. The study shows that detailed studies of peat profiles from ombrotrophic bogs, using appropriate preparatory and analytical methods, can provide new insight into the timing, intensity, and predominant sources of atmospheric Pb contamination, even in samples dating from ancient times.  相似文献   
90.
Tumor therapy with shock waves requires modified lithotripter shock waves   总被引:1,自引:0,他引:1  
The work was supported by the Award for the Advancement of European Science from the Koerber-Stiftung and by Dornier Medizintechnik.  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