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   16338篇
  免费   204篇
  国内免费   137篇
安全科学   476篇
废物处理   605篇
环保管理   2262篇
综合类   3215篇
基础理论   4068篇
环境理论   10篇
污染及防治   3987篇
评价与监测   973篇
社会与环境   956篇
灾害及防治   127篇
  2022年   123篇
  2021年   128篇
  2020年   113篇
  2019年   137篇
  2018年   205篇
  2017年   245篇
  2016年   333篇
  2015年   287篇
  2014年   376篇
  2013年   1369篇
  2012年   489篇
  2011年   650篇
  2010年   517篇
  2009年   580篇
  2008年   649篇
  2007年   678篇
  2006年   643篇
  2005年   515篇
  2004年   505篇
  2003年   509篇
  2002年   443篇
  2001年   545篇
  2000年   434篇
  1999年   249篇
  1998年   202篇
  1997年   195篇
  1996年   209篇
  1995年   226篇
  1994年   213篇
  1993年   208篇
  1992年   220篇
  1991年   207篇
  1990年   208篇
  1989年   176篇
  1988年   155篇
  1987年   136篇
  1986年   165篇
  1985年   161篇
  1984年   166篇
  1983年   168篇
  1982年   165篇
  1981年   165篇
  1980年   153篇
  1979年   150篇
  1978年   109篇
  1977年   121篇
  1974年   111篇
  1973年   91篇
  1972年   110篇
  1971年   90篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
聚苯乙烯基硫代磺酸钾树脂的合成及其与卤代烃的反应   总被引:2,自引:2,他引:0  
吴萼  刘秀芬 《环境化学》1998,17(3):237-242
由聚苯乙烯基磺酰氯树脂与硫化氢钾反应制备聚苯乙烯基硫代磺酸钾树脂(I),树脂I与亲电的卤代烃反应,生成聚苯乙烯基硫代磺酸酯树脂(Ⅱ),树脂Ⅱ经过乙硫醇处理,使卤代烃结构部分以不对称二硫醚的形式游离下来,用GC/MS对其结构进行鉴定。从不对称二硫醚的结构可推导出原卤代烃的结构,所制备的聚苯乙烯基硫代磺酸钾树脂的转化效率为1.11mmol·g^-1。  相似文献   
102.
103.
104.
105.
106.
在活动流场模型的基础上建立了新的溶质运移控制方程,研究了流场分形特征参数的计算方法;采用4组染色示踪试验资料,分析了活动流场模型模拟土壤水流运动和溶质运移宏观非均匀特征的适用性.模拟分析表明,活动流场模型能较准确地捕捉到土壤中的优先流特别是不稳定流的宏观运动特征;土壤存在大孔隙结构的情况下,水流和溶质将更快的迁移到深层土壤,活动流场模型模拟计算的入渗深度偏小,但大于连续性模型的模拟计算结果;当土壤中的大孔隙结构较少时,活动流场模型模拟预测的土壤含水率分布和溶质浓度分布与实测结果比较一致.  相似文献   
107.
INTRODUCTION: Using data from the NASS General Estimates System (GES), the method of induced exposure was used to assess the effects of electronic stability control (ESC) on loss-of-control type crashes for sport utility vehicles. METHOD: Sport utility vehicles were classified into crash types generally associated with loss of control and crash types most likely not associated with loss of control. Vehicles were then compared as to whether ESC technology was present or absent in the vehicles. A generalized additive model was fit to assess the effects of ESC, driver age, and driver gender on the odds of loss of control. In addition, the effects of ESC on roads that were not dry were compared to effects on roads that were dry. RESULTS: Overall, the estimated percentage reduction in the odds of a loss-of-control crash for sport utility vehicles equipped with ESC was 70.3%. Both genders and all age groups showed reduced odds of loss-of-control crashes, but there was no significant difference between males and females. With respect to driver age, the maximum percentage reduction of 73.6% occurred at age 27. The positive effects of ESC on roads that were not dry were significantly greater than on roads that were dry.  相似文献   
108.
This study uses an interactionist approach to examine the moderating effect of follower trait positive affectivity (trait PA) on the relation between transformational leadership and both follower creative performance and organizational citizenship behaviors (OCB). On the basis of responses from 212 employees and their direct supervisors from the research and development department of a company in Mainland China, results support the hypothesized moderation effect. Specifically, the positive influence of transformational leadership on creative performance was significantly reduced for followers who were higher on trait PA (ΔR2 = .02, p < .05). The same pattern, in which followers' trait PA appeared to substitute for the influence of transformational leadership, generalized to the outcome of follower OCB as well (ΔR2 = .04, p < .01). We discussed theoretical and practical implications of these findings. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
109.
110.
Abstract

In many studies, ergonomics has been shown to influence human performance. The aim of this paper was to demonstrate imp ortan t ergonomics influences on quality in industrial production, from the perspective of interactions between humans, technology, organization, and work environment. A second aim was to elab orate on the implications of these findings for the development of quality management strategies. This paper shows that ergonomics problems in terms of adverse work environmental conditions, in appropriate design of technology, and an unsuitable org an izatio n are important causes of quality deficiencies. Problem solving aimed at improving ergonomics, quality, and productivity simultaneously is likely to obtain sup po rt from most of the interest parties of the company, and may also enhance participation. Ergonomics has the potential of becoming a driving force for the development of new quality management strategies.  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