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   87153篇
  免费   1250篇
  国内免费   1264篇
安全科学   3648篇
废物处理   3131篇
环保管理   13493篇
综合类   21161篇
基础理论   25855篇
环境理论   71篇
污染及防治   12987篇
评价与监测   5216篇
社会与环境   3593篇
灾害及防治   512篇
  2022年   814篇
  2021年   812篇
  2020年   662篇
  2019年   872篇
  2018年   1126篇
  2017年   1155篇
  2016年   2139篇
  2015年   1852篇
  2014年   2578篇
  2013年   9247篇
  2012年   2048篇
  2011年   2200篇
  2010年   3219篇
  2009年   3358篇
  2008年   1714篇
  2007年   1529篇
  2006年   1980篇
  2005年   2084篇
  2004年   2362篇
  2003年   2203篇
  2002年   1744篇
  2001年   2010篇
  2000年   1837篇
  1999年   1431篇
  1998年   1351篇
  1997年   1344篇
  1996年   1470篇
  1995年   1553篇
  1994年   1449篇
  1993年   1306篇
  1992年   1290篇
  1991年   1266篇
  1990年   1214篇
  1989年   1186篇
  1988年   1017篇
  1987年   972篇
  1986年   983篇
  1985年   1055篇
  1984年   1151篇
  1983年   1158篇
  1982年   1170篇
  1981年   1093篇
  1980年   936篇
  1979年   909篇
  1978年   815篇
  1977年   710篇
  1976年   638篇
  1975年   593篇
  1973年   619篇
  1972年   622篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
This paper examines the relationship between survivor reactions to a downsizing and retention subsequent to a downsizing. We hypothesize that survivors who experience the downsizing as distributively, procedurally, and interactionally just and who see top management as trustworthy will feel more attached to the organization because each reduces the threat inherent in downsizing. In addition, we hypothesize that survivors who feel empowered will also feel more attached to the organization because they feel better able to cope with the downsizing. We further hypothesize that those survivors who feel more attached to the organization following the downsizing will be more likely to remain with the organization in the coming year. The theoretical model is tested on a sample of aerospace employees who survived an organizational downsizing. The trustworthiness of management, distributive justice, procedural justice, and three dimensions of empowerment are found to facilitate more organizational attachment. Higher levels of attachment are found, in turn, to facilitate less voluntary turnover in the year following the downsizing. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
122.
123.
124.
125.
126.
The effects of food availability, female size, and social interactions on the quality of Pomacentrus amboinensis larvae at hatching were examined using two field-based experiments. In Experiment 1, food availability and female size significantly influenced size, eye diameter and levels of yolk reserves of larvae at hatching. Small females (47 to 52 mm standard length, SL) whose diets were not supplemented, produced the longest larvae (3.0 ± 0.01 mm total length, TL) with the least yolk reserves (50.1 ± 1.04 μm2). Irrespective of female size, those that received additional food produced larvae with the largest yolk-sacs (large females: 87.60 ± 1.53 μm2; small females: 80.14 ± 1.24 μm2). In Experiment 2, interactions with conspecifics had a greater affect on the somatic development of larvae at hatching than food availability. Increased social interactions resulted in larvae that were ⋍3% longer, with 2% greater head depth, than larvae from females that spawned in isolation on the experimental reefs. Fed females produced larvae with ⋍20% more yolk than larvae from females whose diets were not supplemented. All three factors (food availability, female size, and intensity of social interactions) tested within these experiments vary spatially and temporally among reefs. There is the potential, therefore, for larvae at the onset of the planktonic stage to vary in quality, level of development, and probability of survival. Received: 12 August 1996 / Accepted: 26 August 1996  相似文献   
127.
128.
Material suppliers and industrial metabolism   总被引:1,自引:1,他引:0  
Life Cycle Assessment (LCA) is not sufficiently tailored to the analysis of strategic environmental problems of material suppliers. Sustainable development calls for a reduction by a factor of 10 to 20 in the material intensity of the economy, a situation which leads to dramatic shifts in markets for raw materials. Furthermore, a material supplier might have major improvement options in the material’s numerous downstream uses. LCAs, however, can’t cover these two aspects. An adapted form of Substance Flow Analysis (SFA) may be an answer. This approach defines a system in relation to the flow of a specific material through society. All environmental interventions related to the material are inventoried. An emission evaluation indicates the dominant environmental bottlenecks, given the current market volume of each application of the material. This helps to identify improvement options and strategic choices in market portfolios. Scenario analysis on potential measures can further indicate changes of material flows — and thus markets — in the system. The approach is illustrated with a case study on chlorine.  相似文献   
129.
130.
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