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   19721篇
  免费   214篇
  国内免费   176篇
安全科学   534篇
废物处理   741篇
环保管理   2640篇
综合类   3555篇
基础理论   5615篇
环境理论   11篇
污染及防治   4545篇
评价与监测   1189篇
社会与环境   1140篇
灾害及防治   141篇
  2022年   133篇
  2021年   153篇
  2020年   123篇
  2019年   165篇
  2018年   328篇
  2017年   379篇
  2016年   547篇
  2015年   344篇
  2014年   401篇
  2013年   1398篇
  2012年   912篇
  2011年   867篇
  2010年   562篇
  2009年   626篇
  2008年   715篇
  2007年   745篇
  2006年   709篇
  2005年   1045篇
  2004年   1186篇
  2003年   1048篇
  2002年   501篇
  2001年   594篇
  2000年   449篇
  1999年   278篇
  1998年   205篇
  1997年   203篇
  1996年   215篇
  1995年   229篇
  1994年   214篇
  1993年   211篇
  1992年   219篇
  1991年   214篇
  1990年   208篇
  1989年   180篇
  1988年   153篇
  1987年   137篇
  1986年   159篇
  1985年   161篇
  1984年   162篇
  1983年   166篇
  1982年   162篇
  1981年   165篇
  1980年   152篇
  1979年   147篇
  1978年   108篇
  1977年   122篇
  1974年   112篇
  1973年   92篇
  1972年   109篇
  1971年   89篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
251.
252.
253.
254.
The product service systems’ (PSS) sustainability potential is described in the framework of the new types of stakeholder relationships and/or partnerships, producing new convergence of economic interests, and a potential concomitant systemic resources optimization.In this perspective, it is argued that the design competencies should move towards those of the ‘strategic design’, thus introducing the concept of ‘strategic design for sustainability’: the design of an innovation strategy, shifting the business focus from designing (and selling) physical products only, to designing (and selling) a system of products and services which are jointly capable of fulfilling specific client demands, while re-orienting current unsustainable trends in production and consumption practices.Some examples of PSS are presented and discussed using the PSS categories ‘services providing added value to the product life cycle’, ‘services providing final results to customers’, and ‘services providing enabling platforms for customers’. The cases derive from an analysis of the ‘environmental friendly innovation’ yearly endowed prize submissions. The Politecnico di Milano University together with the Bocconi University and Legambiente (an environmental NGO) promotes the initiative in Italy.  相似文献   
255.
Community mitigation of hazard impact requires hazard knowledge and preparedness on the part of the members of diverse and complex communities. Longitudinal research in the tropical cyclone prone north of Australia has gathered extensive datasets on community awareness, preparedness and knowledge, in order to contribute to education campaigns and mitigation strategies. Data have been used to identify issues of vulnerability to cyclones and capacity to deal with the hazard. This has been developed as a community vulnerability and capacity model that may be applied to diverse communities in order to assess levels of capability to mitigate and deal with the cyclone hazard. The model is presented here in a simplified form as its development is evolving and ongoing.  相似文献   
256.
We describe a new method for the post-mortem examination of the fetal central nervous system. The brain is immobilized in gelatin prior to ultrasonic examination. Correlation with prenatal ultrasound is excellent and subsequent pathological examination is enhanced and facilitated.  相似文献   
257.
258.
The impact of prenatal sonographic diagnosis of oesophageal and gastrointestinal obstructions has been analysed over a 10-year period. Three groups of patients were evaluated. The first group consisted of 46 newborns with abnormal prenatal sonogratns, 41 of which were confirmed to have intestinal obstruction postnatally. The second group consisted of 17 neonates with normal prenatal sonograms who had intestinal obstruction postnatally. The third group included 56 newborns who did not undergo a prenatal sonogram but who had intestinal obstruction confirmed at surgery. Polyhydramnios without the appearance of a stomach on ultrasound was diagnostic of pure oesophageal atresia. Polyhydramnios with intestinal dilation was diagnostic of intestinal obstruction. Although surgery was performed earlier in the infants diagnosed prenatally with ultrasound, mortality was no less than in the group that did not undergo a prenatal sonogram, probably because of the high incidence of associated anomalies.  相似文献   
259.
260.
Prenatal diagnosis of trisomy 20 mosaicism was made in two pregnancies by chromosome analysis of cultured amniotic fluid cells. In both cases, the pregnancy continued to term and a healthy male infant was delivered. Regular assessments up to the age of 6-5 years revealed normal physical and intellectual development in both children.  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