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   2111篇
  免费   19篇
  国内免费   19篇
安全科学   73篇
废物处理   93篇
环保管理   264篇
综合类   388篇
基础理论   467篇
环境理论   3篇
污染及防治   596篇
评价与监测   146篇
社会与环境   112篇
灾害及防治   7篇
  2023年   20篇
  2022年   33篇
  2021年   36篇
  2020年   23篇
  2019年   33篇
  2018年   56篇
  2017年   45篇
  2016年   62篇
  2015年   60篇
  2014年   66篇
  2013年   96篇
  2012年   91篇
  2011年   126篇
  2010年   101篇
  2009年   128篇
  2008年   112篇
  2007年   126篇
  2006年   79篇
  2005年   80篇
  2004年   93篇
  2003年   72篇
  2002年   79篇
  2001年   57篇
  2000年   40篇
  1999年   26篇
  1998年   30篇
  1997年   28篇
  1996年   29篇
  1995年   34篇
  1994年   21篇
  1993年   13篇
  1992年   19篇
  1991年   17篇
  1990年   23篇
  1989年   10篇
  1988年   11篇
  1987年   4篇
  1986年   10篇
  1985年   9篇
  1984年   16篇
  1983年   12篇
  1982年   17篇
  1981年   8篇
  1979年   10篇
  1973年   5篇
  1972年   4篇
  1970年   6篇
  1968年   6篇
  1965年   6篇
  1962年   4篇
排序方式: 共有2149条查询结果,搜索用时 484 毫秒
941.
It has been proposed that voluntary urban climate programmes overcome shortfalls in mandatory, top-down, state-led government interventions to address climate change risks. Such programmes seek commitments from households and firms to improve their environmental sustainability, but do not have the force of law. City governments are actively developing and implementing such programmes, seeking improved and accelerated urban climate action. There is little evidence, however, of whether their involvement positively affects voluntary programme performance. This article presents qualitative comparative analysis (QCA) of 26 voluntary programmes from Australia, the Netherlands and the US, seeking to understand whether, and if so how, city governments affect the performance of voluntary urban climate programmes. The results will help to inform city governments about the roles they may play in urban climate governance.  相似文献   
942.
Informal hierarchies are a common and important feature of many groups, yet we know little about the antecedent conditions that determine the strength of such hierarchies. Building on theory that has depicted hierarchy as a mechanism for reducing uncertainty and creating structure, we posit that informal hierarchies emerge most strongly in situations that are ambiguous, ill‐defined, and unstructured. Three independent studies confirm this notion, demonstrating that groups develop particularly strong informal hierarchies in situations characterized by both a lack of strong formal leadership and high task complexity. These findings support the theoretical notion that formal and informal hierarchies are closely related, but only under conditions of high task complexity in which the structuring functions of hierarchies are most crucial.  相似文献   
943.
Background: In 2011, about 30,000 people died in motor vehicle collisions (MVCs) in the United States. We sought to evaluate the causes of prehospital deaths related to MVCs and to assess whether these deaths were potentially preventable.

Methods: Miami–Dade Medical Examiner records for 2011 were reviewed for all prehospital deaths of occupants of 4-wheeled motor vehicle collisions. Injuries were categorized by affected organ and anatomic location of the body. Cases were reviewed by a panel of 2 trauma surgeons to determine cause of death and whether the death was potentially preventable. Time to death and hospital arrival times were determined using the Fatality Analysis Reporting System (FARS) data from 2002 to 2012, which allowed comparison of our local data to national prevalence estimates.

Results: Local data revealed that 39% of the 98 deaths reviewed were potentially preventable (PPD). Significantly more patients with PPD had neurotrauma as a cause of death compared to those with a nonpreventable death (NPD) (44.7% vs. 25.0%, P =.049). NPDs were significantly more likely to have combined neurotrauma and hemorrhage as cause of death compared to PPDs (45.0% vs. 10.5%, P <.001). NPDs were significantly more likely to have injuries to the chest, pelvis, or spine. NPDs also had significantly more injuries to the following organ systems: lung, cardiac, and vascular chest (all P <.05). In the nationally representative FARS data from 2002 to 2012, 30% of deaths occurred on scene and another 32% occurred within 1 h of injury. When comparing the 2011 FARS data for Miami–Dade to the remainder of the United States in that year, percentage of deaths when reported on scene (25 vs. 23%, respectively) and within 1 h of injury (35 vs. 32%, respectively) were similar.

Conclusions: Nationally, FARS data demonstrated that two thirds of all MVC deaths occurred within 1 h of injury. Over a third of prehospital MVC deaths were potentially preventable in our local sample. By examining injury patterns in PPDs, targeted intervention may be initiated.  相似文献   

944.
Rabbits have been suggested as a zoonotic source of Hepatitis E virus. Phylogenetic analysis of HEV isolates from farmed, wild and pet rabbits in the Netherlands (23, 0, and 60 % respectively) showed them to be grouped amongst published rabbit HEV sequences and distinct from most human isolates. Dutch rabbits are unlikely to be a zoonotic source.  相似文献   
945.
946.
In order to successfully inform environmental management, environmental research needs to balance legitimacy, credibility, and salience. This paper aims to identify trade-offs and synergies between these three attributes in collaborative research for environmental management, and draws lessons for organizing such research. Empirically, it draws on a study of a research program on the ecological effects of coastal protection through sand nourishment. Our findings suggest that the legitimacy and salience of knowledge creation, particularly in an interactive governance context, are complementary. At the same time, we found trade-offs between practical relevance and fundamental knowledge creation, as well as between issue diversity and the depth and quality of scientific inquiry. Balancing the legitimacy, credibility, and salience of knowledge may be enabled by interactive knowledge creation involving policy-makers, experts and stakeholders. We conclude that successful management-oriented environmental research, particularly in the case of wicked problems, requires both a careful design of arrangements for stakeholder engagement, and well- established linkages to broader regulatory and institutional contexts.  相似文献   
947.
948.
949.
950.
A new dune area was constructed by beach and foreshore nourishments along the Delfland Coast in the southwestern Netherlands. The new area is intended to be a compensation for losses of existing high quality dunes in nearby areas, due to the use/construction of Maasvlakte 2, the new harbour extension of Rotterdam opening in 2013. The target habitats for compensation include dry grey dunes and moist dune valley grassland. Due to the habitat type, the nourished material had to have a special character. The nourishment was carried out according to a special design and initial development of the new area had to follow certain pathways. In order to meet the compensation requirements in time. Careful monitoring is done to assess whether development of the new habitat is taking place in the direction of the desired target habitats. This paper reports on the construction of the new area and on the first years of development and monitoring. The monitoring mainly concerns development of the abiotic landscape elements, geomorphology, groundwater and soils. The lessons learned from this area are discussed in the light of the development of other recent young nature areas in the sandy Dutch delta coast. This gives new insights for coastal management in general in the context of building with nature.  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