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   20239篇
  免费   285篇
  国内免费   346篇
安全科学   680篇
废物处理   877篇
环保管理   2882篇
综合类   3314篇
基础理论   5515篇
环境理论   7篇
污染及防治   5103篇
评价与监测   1178篇
社会与环境   1186篇
灾害及防治   128篇
  2022年   164篇
  2021年   178篇
  2020年   183篇
  2019年   146篇
  2018年   393篇
  2017年   375篇
  2016年   581篇
  2015年   374篇
  2014年   459篇
  2013年   1439篇
  2012年   1001篇
  2011年   1084篇
  2010年   693篇
  2009年   796篇
  2008年   875篇
  2007年   943篇
  2006年   792篇
  2005年   966篇
  2004年   1110篇
  2003年   942篇
  2002年   581篇
  2001年   675篇
  2000年   536篇
  1999年   344篇
  1998年   214篇
  1997年   238篇
  1996年   225篇
  1995年   274篇
  1994年   217篇
  1993年   210篇
  1992年   177篇
  1991年   190篇
  1990年   181篇
  1989年   186篇
  1988年   154篇
  1987年   133篇
  1986年   157篇
  1985年   143篇
  1984年   191篇
  1983年   148篇
  1982年   172篇
  1981年   158篇
  1980年   130篇
  1979年   149篇
  1978年   94篇
  1977年   98篇
  1975年   88篇
  1974年   95篇
  1973年   87篇
  1972年   98篇
排序方式: 共有10000条查询结果,搜索用时 437 毫秒
41.
42.
Community evacuation following a chlorine release, Mississippi   总被引:1,自引:0,他引:1  
On 7th September 1986, four miles north of Collins, Mississippi, a train transporting chlorine derailed. Two cars ruptured and gas escaped. As a result, 100 families were evacuated. To study the evacuation process, we conducted person-to-person interviews with sixty-two families staying in the evacuation center. Only 52.5% of the families received their first directive to evacuate directly from police or other officials. Delays in evacuating tended to be shorter when people were warned by the police and were told the reason for evacuating. Lack of personal transportation and preexisting health problems resulted in delays in evacuation. Concerns about evacuation included fear of looting, lack of a place to go, lack of transportation, difficulty in moving with children and elderly persons, and the need to take care of pets. One third of the interviewees reported feeling panic. Community evacuation procedures would be improved if: (1) officials contact all households directly; (2) the warning message addresses people's concerns; and (3) transportation is provided.  相似文献   
43.
New data on the composition of surface assemblages of plant macroremains from soil and swamp samples have been obtained in the study of geomorphologically different localities in the middle reaches of the Nizhnyaya Tunguska River. The results of paleocarpological analysis of forest soil sections supported by relevant palynological and geochronological data are presented. Natural changes of the forest cover over the past 2400 years and quantitative characteristics of the paleoclimate during each stage are described.Translated from Ekologiya, No. 1, 2005, pp. 3–10.Original Russian Text Copyright © 2005 by Koshkarova, Koshkarov.  相似文献   
44.
45.
Prader–Willi syndrome (PWS) results from either paternal deletion of 15q11–q13, or maternal uniparental disomy (UPD) of chromosome 15 or imprinting center mutation. Prenatal diagnosis of PWS is currently indicated for chromosomal parental translocation involving chromosome 15 and for decreased fetal movements during the third trimester of gestation. Here we present the prenatal diagnosis of PWS during the first trimester of gestation and autopsy findings. Chorionic villus sampling (CVS) was performed for advanced maternal age at 13 weeks' gestation. CVS showed mosaicism including cells with a normal karyotype and cells with trisomy 15. Amniocentesis showed cells with a normal karyotype. Molecular analysis demonstrated that the fetus had a typical PWS abnormal methylation profile and maternal disomy for chromosome 15. Fetal ultrasound examination showed slightly enlarged lateral ventricles and hypoplasic male external genitalia without intra-uterine growth retardation. The autopsy showed a eutrophic male fetus with facial dysmorphy, hypoplasic genitalia, abnormal position of both feet and posterior hypoplasia of the corpus callosum. This report points out that in a karyotypically normal fetus with ambiguous male external genitalia and cerebral anomalies, extensive cytogenetic and molecular biology studies are strongly recommended because of risk of PWS. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
46.
47.
48.
49.
50.
Baron RC  Etzel RA  Sanderson LM 《Disasters》1988,12(4):356-365
On 11 August 1985, a large inadvertent release occurred from a chemical manufacturing plant in Institute, West Virginia. The emission was related to overheating of a storage tank that contained chemicals for the production of aldicarb, a cholinesterase inhibiting pesticide. As a result of this emission, 136 persons were treated in five local emergency rooms, 29 of whom were hospitalized for one or more days, mostly for observation. No fatalities resulted. Interviews with treated persons and non-treated community residents confirmed that the health effects were transient and compatible with exposure to irritating vapors rather than with exposure to methyl isocyanate (a chemical used in the process) or to aldicarb. Only 5% of the treated persons and 5% of the community residents surveyed were adequately warned of the emission by the plant siren. Because persons in the nearby community are potentially vulnerable to chemical injury, we recommend the development of an improved warning system, a formal evacuation procedure, and other measures to limit exposure of persons in this area in the event of a future release.  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