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   1857篇
  免费   19篇
  国内免费   25篇
安全科学   51篇
废物处理   65篇
环保管理   252篇
综合类   408篇
基础理论   368篇
环境理论   1篇
污染及防治   529篇
评价与监测   98篇
社会与环境   115篇
灾害及防治   14篇
  2023年   18篇
  2022年   18篇
  2021年   31篇
  2020年   22篇
  2019年   26篇
  2018年   51篇
  2017年   52篇
  2016年   62篇
  2015年   75篇
  2014年   78篇
  2013年   85篇
  2012年   86篇
  2011年   116篇
  2010年   101篇
  2009年   103篇
  2008年   92篇
  2007年   102篇
  2006年   83篇
  2005年   58篇
  2004年   81篇
  2003年   46篇
  2002年   62篇
  2001年   71篇
  2000年   30篇
  1999年   18篇
  1998年   18篇
  1997年   27篇
  1996年   21篇
  1995年   32篇
  1994年   19篇
  1993年   7篇
  1992年   18篇
  1991年   26篇
  1990年   11篇
  1989年   20篇
  1988年   7篇
  1987年   4篇
  1985年   6篇
  1984年   5篇
  1983年   4篇
  1982年   10篇
  1981年   10篇
  1979年   9篇
  1978年   4篇
  1970年   6篇
  1969年   4篇
  1965年   4篇
  1960年   4篇
  1959年   3篇
  1954年   3篇
排序方式: 共有1901条查询结果,搜索用时 95 毫秒
921.
922.
Perinatal survival rates after intrauterine transfusions (IUT) for red cell alloimmunisation now exceed 90%, which demonstrates the safety and efficacy of one of the most successful procedures in fetal therapy. However, improved perinatal survival could lead to an increased number of children with long-term disabilities. The importance of long-term follow-up studies in fetal therapy lies in both the necessity of evaluation of antenatal management as well as in evidence-based preconceptional and prenatal counselling. This review describes the possible long-term cardiovascular and neurodevelopmental sequelae after IUT treatment for different indications including red cell alloimmunisation, parvovirus B19 infection, fetomaternal haemorrhage and twin anaemia-polycythaemia sequence. © 2013 John Wiley & Sons, Ltd.  相似文献   
923.
Gender in integrated water management: an analysis of variation   总被引:1,自引:0,他引:1  
Gender is an important variable in water use, policy, and intervention. This article explores this variation and its policy implications. Concepts are applied in several case studies to draw generic conclusions. Variation is related to the purpose of water use (consumptive or productive) and to the local, culture-specific patterns of the intra-household organization of consumption for family welfare (which includes domestic water provision) and income-generation (for which water is an input, especially in rural areas). For domestic water use, the intra-household sharing of unpaid domestic responsibilities is a key gender issue. Water for productive use, on the other hand, is embedded in the gendered organization of household economic activity, as elaborated for smallholder-irrigated agriculture. In female-managed and dual farming systems, where a high proportion of farm decision-makers are women, irrigation agencies need to better target their support. In male-managed farming systems, however, the majority of women lack their own farm enterprise in which water is an input. Women's access to land, markets and credits besides access to water, is at stake. To conclude, given the strong variation in water use along gender lines, gender analysis is indispensable for any concrete water policy and intervention.  相似文献   
924.
925.
926.
927.
The correlation between climatic changes and the numbers of trees in the generations of Siberian spruce (Picea obovata Ledeb.) in subgoltsy tree stands of the Southern Urals was analyzed over the past 200 years. The results showed that the most abundant generations appeared in 1809–1816, 1821–1827, 1839–1845, 1850–1867, 1875–1887, 1891–1896, 1900–1904, 1911–1918, 1923–1932, 1944–1952, 1958–1966, and 1975–1995. Their formation proved to be related to the improvement of thermal conditions of the warm season during the five to seven years before and after the emergence of trees and conditions of the cold season in the year of their emergence, as well as to the periods of increased snow depth in late April in the years 27–32 of tree growth.  相似文献   
928.
As part of the UN-ECE Intensive Monitoring Program, data on precipitation, throughfall and soil solution concentrations are measured on a regular basis in approximately 300 forest stands. These data were used to construct element budgets for European forests. To construct such budgets drainage fluxes have to be modeled. In this paper, the research chain from model selection to data derivation and application of the selected model to 245 of the 300 sites is described. To select a suitable hydrological model the Cl- balance method, two capacity models (a multi and a single layer version) and a Darcy model have been applied to two forest sites. The results indicate that drainage fluxes calculated with the Darcy model are more accurate than fluxes derived with the capacity model, in particular in situations where water availability is limited. The Darcy model was applied to the sites using a mixture of generic data and site data. Despite the use of generic data, the calculated drainage fluxes appear feasible. Median transpiration fluxes were 350 mm and the lowest values are found in northern Europe and highest values are found in central Europe. Median drainage fluxes were 150 mm yr-1 with the highest values in areas with high rainfall. Uncertainty analyses indicate that the use of local instead of interpolated meteorological data leads to lower drainage fluxes at 70% of the sites. The median deviation in calculated drainage fluxes is 20 mm yr-1. The use of local soil data had little impact on the calculated fluxes.  相似文献   
929.
930.
In this paper we argue that organizational identification is predictive of employee interests and concerns during periods of organizational change. More specifically, we assert that organizational identification may largely determine whether employees may be focused upon the change related outcomes (e.g., salary, expenses, etc.), or on the change processes (e.g., procedures, voice and participation options, etc.). Data of both a scenario experiment and a survey are presented indicating that high and low identifiers indeed are differentially interested in process and outcome information. The results suggest that people who identify less with the organization are more likely to be focused upon the change outcomes then on the change process, while people who identify highly (i.e., deep structure) with the organization are more likely to be focused upon the change processes then on the change outcomes. The benefits of awareness of organizational members' level of identification for organizational change management are discussed. Copyright © 2006 John Wiley & Sons, Ltd.  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