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   21573篇
  免费   387篇
  国内免费   373篇
安全科学   858篇
废物处理   875篇
环保管理   3629篇
综合类   3362篇
基础理论   5603篇
环境理论   15篇
污染及防治   5375篇
评价与监测   1264篇
社会与环境   1174篇
灾害及防治   178篇
  2023年   132篇
  2022年   204篇
  2021年   205篇
  2020年   226篇
  2019年   199篇
  2018年   390篇
  2017年   368篇
  2016年   547篇
  2015年   417篇
  2014年   584篇
  2013年   1749篇
  2012年   791篇
  2011年   1129篇
  2010年   841篇
  2009年   960篇
  2008年   1041篇
  2007年   1093篇
  2006年   912篇
  2005年   772篇
  2004年   779篇
  2003年   681篇
  2002年   649篇
  2001年   718篇
  2000年   596篇
  1999年   374篇
  1998年   268篇
  1997年   275篇
  1996年   275篇
  1995年   332篇
  1994年   271篇
  1993年   263篇
  1992年   222篇
  1991年   218篇
  1990年   210篇
  1989年   212篇
  1988年   177篇
  1987年   167篇
  1986年   187篇
  1985年   178篇
  1984年   229篇
  1983年   182篇
  1982年   212篇
  1981年   196篇
  1980年   157篇
  1979年   162篇
  1978年   117篇
  1977年   112篇
  1975年   93篇
  1974年   97篇
  1972年   102篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
91.
In this article the authors assert that successful long-term pollution prevention will require changes in the culture and business practices of an organization such that the term “pollution prevention” eventually becomes obsolete. They envision firms evolving to a point where actions that today are referred to as pollution prevention will simply be part of standard business practices and thoroughly embedded in the firms' culture. Although pollution prevention projects and programs need to be highly visible at the outset to communicate throughout the organization and to demonstrate the benefits that can be gained, companies should adopt a long-term strategy aimed at making fundamental changes in the way they do business, rather than relying solely on piecemeal projects and special plans or programs. Such evolution of the firm will maximize the chances of meeting the dual challenges of business competitiveness and environmental stewardship. This article presents a vision for integrating environmental performance with business objectives and suggests practical steps to begin moving toward that vision.  相似文献   
92.
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   
93.
94.
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   
95.
96.
97.
98.
99.
100.
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