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   3624篇
  免费   72篇
  国内免费   33篇
安全科学   129篇
废物处理   113篇
环保管理   646篇
综合类   675篇
基础理论   916篇
环境理论   9篇
污染及防治   834篇
评价与监测   203篇
社会与环境   155篇
灾害及防治   49篇
  2023年   13篇
  2022年   19篇
  2021年   40篇
  2020年   24篇
  2019年   37篇
  2018年   83篇
  2017年   83篇
  2016年   90篇
  2015年   93篇
  2014年   104篇
  2013年   253篇
  2012年   162篇
  2011年   212篇
  2010年   157篇
  2009年   172篇
  2008年   181篇
  2007年   211篇
  2006年   212篇
  2005年   154篇
  2004年   108篇
  2003年   108篇
  2002年   122篇
  2001年   66篇
  2000年   62篇
  1999年   51篇
  1998年   55篇
  1997年   66篇
  1996年   49篇
  1995年   57篇
  1994年   58篇
  1993年   38篇
  1992年   35篇
  1991年   29篇
  1990年   31篇
  1989年   17篇
  1988年   17篇
  1987年   15篇
  1986年   19篇
  1985年   21篇
  1984年   20篇
  1983年   22篇
  1982年   19篇
  1981年   18篇
  1980年   18篇
  1979年   22篇
  1978年   18篇
  1965年   15篇
  1964年   12篇
  1957年   17篇
  1955年   13篇
排序方式: 共有3729条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
Stakeholder theory, originally introduced in 1984 by philosopher Edward Freeman, is among the most influential theories today addressing the complex interplay of societal actors. It underwent several transformations and expansions, but the original Freeman model as well as the latest approaches places the corporation at the center positioning the theory as management driven. In this article—from a sustainability science perspective—we argue that sustainability could also be considered as the center, around which societal actors are grouped, because everyone, individuals as well as stakeholders, have a stake in a ‘common future’ that is built on the transformative concept of sustainability. Next to this shift of perspective from corporation to sustainability at the center, we advance the concept of sustainability stakeholders with the new paradigm of the digital age we (are about to) live in: the proposed sustainability-centered stakeholder theory is developed to incorporate novel parameters as brought about by digitalization (such as big data, real-time transparency, algorithmic correlations, predictive analytics, or changing privacy standards). Hence, we classify the stakeholders of sustainability according to their roles as “big data stakeholders:” collectors, generators, and utilizers of big data. This digital sustainability stakeholder model operationalizes the complex interplay between stakeholders focused on their ‘stake’ in sustainability and a common future and illustrates their roles in the digital age. Thus, it offers a normative framework to analyze stakeholders’ responsibility to contribute to, advance, promote, and achieve sustainability.  相似文献   
996.
997.
998.
999.
Prenatal molecular genetic diagnosis for Noonan syndrome I is reported. Noonan syndrome was suspected because of large cystic hygroma colli, massive pleural effusion and ascites at 23 weeks of gestation and normal karyotype (46,XX). DNA was prepared from amnion cells and screened for mutations in the PTPN11 gene. In exon 8, a missense mutation (S285F) was found. Delivery was induced at 33 weeks of gestation because of silent cardiotocography (CTG). Despite immediate drainage of the hydrothorax, mechanical ventilation was insufficient and the child died 9 h after birth due to severe pulmonary hypoplasia. Pleural punctate was enriched for small lymphocytes and thus was characterized as chylus. Prenatal ultrasound findings in Noonan syndrome usually are unspecific and rarely lead to a diagnosis. However, with the combination of cystic hygroma, pleural effusion, ascites and normal karyotype Noonan syndrome should be considered and DNA testing for PTPN11 mutations may be appropriate. Malformations of lymphatic vessels and/or chylothorax in Noonan syndrome seem to be more frequent than usually anticipated. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
1000.
Irrigated agriculture has resulted in substantial changes in water flows to the lower reaches of the River Murray. These changes have led to large-scale occurrences of dieback inEucalyptus largiflorens (black box) woodlands as well as increased inputs of salt to the river. Management options to address problems of this scale call for the use of spatial data sets via geographic information systems (GIS). A GIS exists for one floodplain of the River Murray at Chowilla, and a simple model predicted six health classes ofEucalyptus largiflorens based on groundwater salinity, flooding frequency, and groundwater depth.To determine the usefulness of the model for vegetation management, the quality of both the model and the GIS data sets were tested. Success of the testing procedure was judged by the degree of spatial matching between the model's predictions of health and that assessed from aerial photographs and by field truthing. Analyses at 80 sites showed that tree health was significantly greater where groundwater salinity was less than 40 dS/m or flooding occurred more frequently than 1 in 10 years or depth to groundwater exceeded 4 m. Testing of the GIS data sets found that vegetation was misclassified at 15% of sites. Association was shown between GIS-predicted values and field-truthed values of groundwater salinity but not groundwater depth. The GIS model of health is a useful starting point for future vegetation management and can be further improved by increasing the quality of the data coverages and further refining of the model to optimize parameters and thresholds.  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