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   1901篇
  免费   51篇
  国内免费   20篇
安全科学   129篇
废物处理   82篇
环保管理   446篇
综合类   210篇
基础理论   490篇
环境理论   2篇
污染及防治   385篇
评价与监测   124篇
社会与环境   72篇
灾害及防治   32篇
  2023年   14篇
  2022年   24篇
  2021年   22篇
  2020年   26篇
  2019年   24篇
  2018年   47篇
  2017年   61篇
  2016年   68篇
  2015年   64篇
  2014年   60篇
  2013年   131篇
  2012年   86篇
  2011年   155篇
  2010年   100篇
  2009年   88篇
  2008年   114篇
  2007年   125篇
  2006年   120篇
  2005年   72篇
  2004年   71篇
  2003年   71篇
  2002年   59篇
  2001年   40篇
  2000年   28篇
  1999年   30篇
  1998年   28篇
  1997年   15篇
  1996年   25篇
  1995年   16篇
  1994年   20篇
  1993年   17篇
  1992年   17篇
  1991年   9篇
  1990年   11篇
  1989年   5篇
  1988年   10篇
  1987年   15篇
  1986年   10篇
  1985年   5篇
  1984年   9篇
  1983年   6篇
  1982年   10篇
  1981年   4篇
  1980年   5篇
  1979年   6篇
  1969年   3篇
  1937年   2篇
  1936年   2篇
  1935年   3篇
  1926年   2篇
排序方式: 共有1972条查询结果,搜索用时 250 毫秒
301.

Introduction

The purpose of the current study was to examine differences in factors associated with self-reported collision involvement of three age groups of drivers based on a large representative sample of Ontario adults. Method: This study was based on data from the CAMH Monitor, an ongoing cross-sectional telephone survey of Ontario adults 18 years and older from 2002 to 2005. Three age groups were examined: 18-34 (n = 1,294), 35-54 (n = 2,428), and 55+ (n = 1,576). For each age group sample, a logistic regression analysis was conducted of self-reported collision involvement in the last 12 months by risk factor measures of driving exposure (kilometers driven in a typical week, driving is stressful, and driving on busy roads), consuming five or more drinks of alcohol on one occasion (past 12 months), cannabis use (lifetime, and past 12 months), and driving after drinking among drinkers (past 12 months), controlling for demographics (gender, region, income, and marital status). Results: The study identified differences in factors associated with self-reported collision involvement of the three age groups of adult drivers. The logistic regression model for the youngest group revealed that drivers who reported that driving was stressful at least some of the time, drank five or more drinks on an occasion, and drove after drinking had an increased risk of collision involvement. For the middle age group, those who reported using cannabis in the last 12 months had significantly increased odds of reporting collision involvement. None of the risk factor measures showed significant associations with collision risk for older drivers (aged 55+). Impact: The results suggest potential areas for intervention and new directions for future research.  相似文献   
302.
This research examines the willingness of employees to follow their organization when the entire business unit is geographically relocating. The site for the study was a large government defense agency moving from a major U.S. northeastern metropolitan area to a rural area south of Washington, D.C. The study participants were 380 employees who were deciding within the next 6 months if they would relocate, too. Attachment to the present community, attachment to the current organization, and availability of job market alternatives are the factors most significantly associated with willingness to move during corporate relocation. © 1998 John Wiley & Sons, Ltd.  相似文献   
303.
Although the literature on employee involvement suggests that some organizations experience significant benefits to employee attitudes and productivity, the results from individual studies vary widely. This study focuses on those factors that may mediate the success or failure of employee involvement practices, especially the role played by middle managers. A postal survey of 155 organizations examined the perceived outcomes of different employee involvement practices and the support or resistance attributed to middle managers. Hypothesized correlates of middle management resistance to employee involvement were examined. As hypothesized, positive outcomes of employee involvement were lower in organizations that experienced middle management resistance. The study supports the view that middle managers may resist employee involvement practices in response to threats to self interest (managerial job loss and delayering). However, lack of congruence between organizational systems and structures and the goals of EI and divided or unclear senior management support for EI were also found to be strongly related to middle management resistance. © 1998 John Wiley & Sons, Ltd.  相似文献   
304.
This study tested the proposition that relationships among the various types of work-related commitment and job performance are affected by both the form of commitment and the facet of performance under consideration. Results provided some support for this view. As hypothesized, job involvement was related only to performance tied to intrinsically rewarding elements of work, and career commitment was positively related to overall performance effectiveness. Unexpectedly, however, organizational commitment (both affective and continuance) was unrelated to job performance. The discussion is centered on practical implications of these findings and on directions for future research. © 1998 John Wiley & Sons, Ltd.  相似文献   
305.
Harmful algal blooms (HABs) diminish the utility of reservoirs for drinking water supply, irrigation, recreation, and ecosystem service provision. HABs decrease water quality and are a significant health concern in surface water bodies. Near real-time monitoring of HABs in reservoirs and small water bodies is essential to understand the dynamics of turbidity and HAB formation. This study uses satellite imagery to remotely sense chlorophyll-a concentrations (chl-a), phycocyanin concentrations, and turbidity in two reservoirs, the Grand Lake O′ the Cherokees and Hudson Reservoir, OK, USA, to develop a tool for near real-time monitoring of HABs. Landsat-8 and Sentinel-2 imagery from 2013 to 2017 and from 2015 to 2020 were used to train and test three different models that include multiple regression, support vector regression (SVR), and random forest regression (RFR). Performance was assessed by comparing the three models to estimate chl-a, phycocyanin, and turbidity. The results showed that RFR achieved the best performance, with R2 values of 0.75, 0.82, and 0.79 for chl-a, turbidity, and phycocyanin, while multiple regression had R2 values of 0.29, 0.51, and 0.46 and SVR had R2 values of 0.58, 0.62, and 0.61 on the testing datasets, respectively. This paper examines the potential of the developed open-source satellite remote sensing tool for monitoring reservoirs in Oklahoma to assess spatial and temporal variations in surface water quality.  相似文献   
306.
This study applied theory from the employee learning and development literature to examine factors related to employees' perceptions of being job content plateaued and hierarchically plateaued. Results indicated that both types of plateauing were related to support from top management, career planning, job involvement, and education level. Furthermore, career exploration, motivation to learn, organizational tenure, and job tenure were related to perceptions of hierarchical plateauing, while supervisor support was related to job content plateauing. Additionally, the two types of plateauing differed in the relative strength of their relationship with the variables studied. Implications and future research suggestions are provided. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   
307.
308.
309.
替代脊椎动物进行化学物质和污染物危害评估的方法已成为越来越重要的需求。现在首先要考虑的是当启动一个脊椎动物生态毒性测试,必须确保不必要的脊椎动物生物的使用尽可能最小化。对于一些监管目的,脊椎动物的使用对环境风险评估(ERA)已经被禁止,而在其他情况下生物测试的数量已经大大减少了,或者测试程序严格精简了。然而,想要获得能够完全替代脊椎动物提供环境危害数据的方法仍有很长的路要走。动物替代品的发展不仅仅是基于道德的考虑,也可以降低执行脊椎动物生态毒性测试的成本以及在某些情况下能够提供更好的信息旨在改进环境风险评估。本文集中综述了在过去的几十年里生态毒性评估替代方法所发生的重大的进展。
精选自Adam Lillicrap, Scott Belanger, Natalie Burden, David Du Pasquier, Michelle R. Embry, Marlies Halder, Mark A. Lampi, Lucy Lee, Teresa Norberg-King, Barnett A. Rattner, Kristin Schirmer, Paul Thomas. Alternative approaches to vertebrate ecotoxicity tests in the 21st century: a review of developments over the last two decades and current status. Environmental Toxicology and Chemistry: Volume 35, Issue 11, pages 2637–2646, November 2016. DOI: 10.1002/etc.3603
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3603/full
  相似文献   
310.
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