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   29616篇
  免费   327篇
  国内免费   224篇
安全科学   833篇
废物处理   1065篇
环保管理   4037篇
综合类   4744篇
基础理论   8552篇
环境理论   21篇
污染及防治   7731篇
评价与监测   1746篇
社会与环境   1247篇
灾害及防治   191篇
  2022年   182篇
  2021年   185篇
  2019年   215篇
  2018年   391篇
  2017年   380篇
  2016年   555篇
  2015年   494篇
  2014年   678篇
  2013年   2134篇
  2012年   843篇
  2011年   1256篇
  2010年   1031篇
  2009年   1039篇
  2008年   1252篇
  2007年   1334篇
  2006年   1187篇
  2005年   1009篇
  2004年   1007篇
  2003年   939篇
  2002年   941篇
  2001年   1240篇
  2000年   862篇
  1999年   549篇
  1998年   427篇
  1997年   436篇
  1996年   442篇
  1995年   482篇
  1994年   438篇
  1993年   396篇
  1992年   414篇
  1991年   373篇
  1990年   377篇
  1989年   411篇
  1988年   349篇
  1987年   300篇
  1986年   276篇
  1985年   307篇
  1984年   286篇
  1983年   323篇
  1982年   322篇
  1981年   271篇
  1980年   245篇
  1979年   271篇
  1978年   231篇
  1977年   198篇
  1976年   200篇
  1975年   192篇
  1974年   173篇
  1973年   171篇
  1972年   202篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
932.
933.
934.

Objective

The objective of this study was to evaluate repeated patient handling injuries following a multi-factor ergonomic intervention program among health care workers.

Methods

This was a quasi-experimental study which had an intervention group and a non-randomized control group. Data were collected from six hospitals in Saskatchewan, Canada from September 1, 2001 to December 1, 2006.

Results

A total of 1,480 individuals who had a previous injury were eligible for the study. Medium and small size hospitals in the intervention group had significantly fewer repeated injuries than in the control group. Multivariate analysis showed that the intervention group had 38.1% lower odds of having repeated injury compared to the control group, after adjusting for hospital size.

Conclusions

The work-related repeated injury after a multi-factor intervention program was reduced. The synergistic relationships between components of multi-factor intervention and applicability of injury prevention programs to different settings need to be further explored.

Impact on Industry

Implementing a multi-factor program with the right equipment and training can lower the risk of injury among health care workers.  相似文献   
935.
936.
A modelling strategy has been developed for consequence analysis of medium and large scale gaseous detonation. The model is based on the solution of Euler equations with one-step chemistry. The Van Leer flux limited method which is a total variation diminishing scheme is used for shock capturing. Preliminary calculations were firstly conducted for small domains with fine grids which resolve the wave, relatively coarse grids which have less than 10 grids across the wave and coarse grids in which the minimum grid size is larger than the wave thickness to ensure that the reaction scheme has been properly tuned to capture the correct detonation pressure, temperature and velocity in the resolutions used in the different cases. The model was firstly tested against a medium scale detonation test in a shock tube with U-bends. Reasonably good agreement is achieved on detonation pressure and mean shock wave velocities at different measuring segments of the tube. Following the validation, the detonation of a hypothetical planar propane-air cloud is simulated. The predictions uncovered some interesting features of such large scale detonation phenomena which are of significance in the safety context, especially for accidental investigations. The findings from the present analysis are in line with the forensic evidence on damages in some historic accidents and challenges previous analysis of a major accident in which forensic evidence suggested localised detonation but was considered as the consequence of fire storms by the investigation team.  相似文献   
937.
938.
939.
940.
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