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   328篇
  免费   3篇
  国内免费   4篇
安全科学   12篇
废物处理   11篇
环保管理   56篇
综合类   82篇
基础理论   50篇
环境理论   1篇
污染及防治   102篇
评价与监测   6篇
社会与环境   15篇
  2022年   4篇
  2021年   13篇
  2020年   2篇
  2019年   4篇
  2018年   6篇
  2017年   7篇
  2016年   12篇
  2015年   7篇
  2014年   9篇
  2013年   35篇
  2012年   15篇
  2011年   17篇
  2010年   17篇
  2009年   5篇
  2008年   16篇
  2007年   11篇
  2006年   17篇
  2005年   10篇
  2004年   5篇
  2003年   9篇
  2002年   12篇
  2001年   5篇
  1998年   3篇
  1997年   5篇
  1995年   3篇
  1994年   3篇
  1993年   3篇
  1992年   3篇
  1991年   4篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1985年   3篇
  1983年   2篇
  1982年   3篇
  1981年   5篇
  1980年   4篇
  1978年   3篇
  1966年   2篇
  1964年   2篇
  1962年   4篇
  1961年   2篇
  1959年   2篇
  1958年   3篇
  1931年   2篇
  1924年   3篇
  1917年   1篇
  1916年   3篇
  1914年   1篇
  1913年   2篇
排序方式: 共有335条查询结果,搜索用时 15 毫秒
121.
122.
The content of polychlorinated biphenyls in Mexican cereals and in their packaging materials was determined. All the samples had polychlorinated biphenyls. In all the food samples and in 73% of the packings, the concentrations of polychlorinated biphenyls exceeded the tolerance limits established by the U.S. Food and Drug Administration. A correlation was found between the values for polychlorinated biphenyls in the cereals and those in their packings, therefore, it is concluded that the main source of polychlorinated biphenyls in Mexican cereals is the transference of those present in the recycled paperboard used for the packings.  相似文献   
123.
We present the first confirmed case by molecular analysis of a metaphyseal chondrodysplasia, McKusick type, in a 22-week fetus. Two novel compound heterozygous mutations, 64T> A and 79G > T, were found in the highly conserved regions of the RMRP gene. Twenty-two heterozygous g.1018 T> C mutations, two homozygous g.1018 T> C mutations, two heterozygous insertion mutations g.799_g.800insC and one heterozygous insertion mutation g.849_g.850insT were found among 100 normal controls. Careful radiological examination of the fetus for skeletal dysplasia allowed definitive diagnosis, proper genetic counselling and future prenatal diagnosis. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
124.
Since highly pathogenic avian influenza virus H5N1 emerged in 1997, avian influenza is considered one of the most important infectious diseases globally. In respect of virus transmission to humans, the consumption of raw poultry products remains of serious concern. In this study, data about survival time and inactivation kinetics of two low pathogenic avian influenza virus (AIV) strains (H3N8, H5N6) in short fermented raw sausage were obtained. In addition, the impact of the preserving factors d,l-lactic acid and sodium chloride on virus infectivity was evaluated through in vitro studies. Virus infectivity was confirmed in embryonated chicken eggs. Inactivation of H3N8 was seen in d,l-lactic acid solutions (0.15 and 0.20%, pH 4.40–4.70 and pH 3.80–3.91) at both temperatures (20 vs. 4°C) during 3 days of exposure. However, infectious virus particles could still be detected after exposure to 0.1% d,l-lactic acid (pH 5.80–5.99). In all NaCl solutions (2, 6 and 12% w/v), infectivity of the H3N8 strain decreased steadily but reduction of the virus titre increased significantly with higher temperature. In raw sausages, decline in virus titre was observed for both strains during ripening and storage. Thereby, decline of virus infectivity was dependent on time and temperature with a more marked effect at higher temperatures (22 vs. 7°C). At refrigeration (7°C), both viruses maintained infectivity over 14 days. Results indicate that appropriate processing of short fermented raw poultry sausage is likely to reduce risk of virus exposure due to adequate inactivation of AIV during ripening and storage.  相似文献   
125.
The Appellate Body report in January 2012 had supported the decision of Panel in the “China-measures related to the exportation of various raw materials” case (WT/DS394,395,398) and affirmed that China’s restrictions (such as tariffs and quota measures) on the exportation of raw materials violated rules put forth by the WTO, which were required to be modified. In this case China’s right to invoke Article 20 of GATT1994 (“general exception”) to justify its exemption from the guidelines in Article 11.3 of the WTO Accession Protocol was denied by the Panel and the Appellate Body. This was due to the fact that the phrasing in Article 11.3 of Protocol failed to mention “GATT.” This was the consequence of the two interpretation approaches the Dispute Settlement Body (DSB) adopted – a narrow textual interpretation and a subjective presumption of “legislative silence.” The inappropriate use of the two methods of interpretation lead to an imbalance between the right and obligation of China under the additional obligations that were imposed upon China by the WTO, which create a negative impact on China’s rare earth case and the protection of domestic natural resources.  相似文献   
126.

The solid and liquid wastes generated from cassava-based industries are organic and acidic in nature, which leads to various global concerns—primarily global warming and biodiversity loss. But the conversion of these wastes into value-added products associated with environmental pollution control contributes to sustainable development. Generally, the thermochemical process such as pyrolysis and gasification and biochemical processes such as anaerobic digestion have been applied for the conversion of cassava waste into value-added products. This review addresses the valorization of cassava wastes, which fulfill almost all needs of the hour, such as energy (biofuel), wastewater treatment (adsorbents), bioplastics, starch nanoparticles, organic acid production, and antimicrobial agents. The major aim of this paper is to analyze and provide the disclosure of the efficiency of cassava-based industrial waste as a source to minimize the problem associated with conventional fossil fuels and through which mitigate the impact of global warming and climate change. Furthermore, recent research and achievements in the valorization of cassava waste have been highlighted.

  相似文献   
127.
Voie OA  Johnsen A  Rossland HK 《Chemosphere》2002,46(9-10):1367-1372
Accumulation of polychlorinated biphenyls (PCBs) in blue mussels (Mytilus edulis) and semipermeable membrane devices (SPMDs) was still high after the removal of PCB contaminated sediments from a Norwegian fjord by dredging. The accumulation of low chlorinated PCB congeners with a low octanol water-partitioning coefficient (Kow) in blue mussels and SPMDs was higher than for the highly chlorinated congeners with a high Kow. The accumulation of low chlorinated congeners was also higher in a lightly contaminated area compared to a highly contaminated area. That dredging the contaminated sediments was unsuccessful in lowering PCB levels in the biota may be for the following reasons: (1) Due to the low solubility of PCBs in the water it is possible that a decrease in the sediment concentration of PCB would leave the water concentrations of PCB unchanged. (2) Removal of the fine organic sediments may also play an important role, since a seabed with coarse inorganic material has a lesser ability to bind PCB. (3) The dredging may whirl up fine contaminated particles that eventually settles on the seabed producing a thin contaminated sediment layer that determine the water concentration. (4) Bioaccumulation in blue mussels and in the SPMDs occurs mostly from PCB dissolved in the water column. Since the water concentration of PCB is unchanged by the dredging, the accumulation in SPMDs and mussels is the same as before dredging. Further monitoring need to be carried out to report the long-term effect of the dredging.  相似文献   
128.
Mass spectrometry is a powerful tool for the analysis of organic pollutants in the environment. Nevertheless, sample preparation for GC/MS analysis is often criticized for being too laborious and requiring expensive equipment. Thus, purge-and-trap or headspace devices are the most popular nowadays to investigate volatile organic pollutants. At the same time, modern commercial high-resolution mass spectrometers allow for the significant simplification of the sample preparation procedures due to better acquisition rate, accurate mass measurements, and improved sensitivity. Here, we used a time-of-flight high-resolution mass spectrometer Pegasus GC-HRT (LECO, USA) to identify and quantify 47 volatile priority organic pollutants in water. The developed accelerated water sample preparation approach requires just 1 mL of water and 1 mL of dichloromethane. The detection limits of the analytes are about 1 μg L?1, while the quantification limits are approximately 5 μg L?1. These limits correspond to those required by Method 8260C of the United States Environmental Protection Agency. Here, we demonstrate that sample preparation for the reliable and sensitive GC/MS analysis of volatile organic priority pollutants may be achieved in 5 min in 5-mL vials in the field or just prior to GC/MS analysis in the laboratory without the use of any expensive equipment.  相似文献   
129.
Previous studies suggested environmental exposures, including mercury (Hg) and lead (Pb), may be related to Wegener's granulomatosis. In this study, investigations were extended to include the measurement of heavy metals in blood samples from patients diagnosed with Wegener's. Diagnosis was confirmed by using the 1990 Classification Criteria for Wegener's granulomatosis established by the American College of Rheumatology (ACR). Using commercial lab testing, whole blood heavy metal screenings were obtained from patients, and results were then compared with validated subject self-report questionnaire estimates of exposure. Thirty-eight Wegener's patients were enrolled; 10 of the 38 exhibited abnormal lab values. In those 10 subjects 3 had elevated nickel (Ni), 7 with increased cobalt (Co), 3 with higher manganese, 1 with elevated copper, and 1 with increased Hg. Overall, the questionnaire results did not correlate with the blood heavy metal analysis. Approximately 26% of Wegener's subjects in this study displayed abnormal heavy metal levels. These findings are likely underestimates since blood levels are an insensitive means for assessing total body burden of heavy metals. From these preliminary studies it appears that elevated Co is a common finding in Wegener's patients but Ni and Hg were also found to be increased. The proportion of patients with abnormal heavy metal levels is more than expected by chance alone. In order to yield more definitive results, further analysis is needed with a larger data set, more controls and more sensitive measurements (hair, urine, or nail samples).  相似文献   
130.
Objective. The provision of appropriate personal cooling vests is recognized as an effective measure to combat heat stress. However, personal cooling vests are not widely implemented in the Hong Kong industries. The current study aims to evaluate the usability of a hybrid cooling vest that is associated with the success of its application in industrial settings. Methods. A self-administrated questionnaire focusing on 10 subjective attributes of cooling effect, ergonomic design and usability of a hybrid cooling vest was administered with 232 occupational workers in the construction, horticultural and cleaning, airport apron services and kitchen and catering industries. Results. A structural equation model estimated by analysis of moment structures was constructed to evaluate the usability of the cooling vest, as influenced by cooling effect and ergonomic design. Results showed that cooling effect (path coefficient?=?0.69, p?p?Conclusions. The structural equation model is feasible to examine the complex nature of the structural relationships among the subjective perceptions of personal cooling vests. The empirical findings furnish sound evidence for further optimization of the hybrid cooling vest in terms of cooling effect and ergonomic design for occupational workers.  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