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   554篇
  免费   14篇
  国内免费   9篇
安全科学   31篇
废物处理   21篇
环保管理   76篇
综合类   85篇
基础理论   143篇
环境理论   1篇
污染及防治   150篇
评价与监测   47篇
社会与环境   19篇
灾害及防治   4篇
  2023年   4篇
  2022年   16篇
  2021年   22篇
  2020年   17篇
  2019年   18篇
  2018年   16篇
  2017年   23篇
  2016年   22篇
  2015年   13篇
  2014年   25篇
  2013年   56篇
  2012年   21篇
  2011年   41篇
  2010年   25篇
  2009年   27篇
  2008年   35篇
  2007年   28篇
  2006年   25篇
  2005年   18篇
  2004年   12篇
  2003年   8篇
  2002年   15篇
  2001年   18篇
  2000年   2篇
  1999年   6篇
  1998年   3篇
  1997年   4篇
  1995年   6篇
  1994年   5篇
  1993年   2篇
  1992年   5篇
  1991年   3篇
  1990年   3篇
  1989年   4篇
  1986年   2篇
  1983年   2篇
  1980年   1篇
  1979年   2篇
  1978年   2篇
  1976年   1篇
  1974年   1篇
  1973年   1篇
  1968年   1篇
  1966年   2篇
  1963年   1篇
  1961年   2篇
  1960年   2篇
  1954年   1篇
  1937年   1篇
  1936年   1篇
排序方式: 共有577条查询结果,搜索用时 15 毫秒
1.
RAMP I is a screening tool developed to support practitioners in screening for work-related musculoskeletal disorder risk factors related to manual handling. RAMP I, which is part of the RAMP tool, is based on research-based studies combined with expert group judgments. More than 80 practitioners participated in the development of RAMP I. The tool consists of dichotomous assessment items grouped into seven categories. Acceptable reliability was found for a majority of the assessment items for 15 practitioners who were given 1?h of training. The usability evaluation points to RAMP I being usable for screening for musculoskeletal disorder risk factors, i.e., usable for assessing risks, being usable as a decision base, having clear results and that the time needed for an assessment is acceptable. It is concluded that RAMP I is a usable tool for practitioners.  相似文献   
2.
3.
4.
Emissions trading is anattractive candidate for implementinggreenhouse gas mitigation, because it canpromote both efficiency and equity. Thispaper analyzes the interregional impacts ofalternative allocations of carbon dioxideemission permits within the U.S. Theanalysis is performed with the aid of anonlinear programming model for ten EPARegions and for six alternative permitdistribution formulas. The reason thatvarious alternatives need to be consideredis that there is no universal consensus onthe best definition of equity. Advanceknowledge of absolute and relative regionaleconomic impacts provides policy-makerswith a stronger basis for making thechoice. The analysis yields several usefulresults. First, the simulations indicatethat no matter how permits are allocated,this policy instrument can substantiallyreduce the cost of GHG mitigation for theU.S. in comparison to a system of fixedquotas for each of its regions. Interestingly, the welfare impacts ofseveral of the allocation formulas differonly slightly despite the large differencesin their philosophical underpinnings. Also, the results for some equity criteriadiffer greatly from their application inthe international domain. For example, theEgalitarian (per capita) criterion resultsin the relatively greatest cost burdenbeing incurred by one of the regions of theU.S. with the lowest per capita income.  相似文献   
5.
Amniocentesis and subsequent tests are reported on a fetus conceived of a rare mating type: its mother has an intermediate level of β hexosaminidase A (HEX A), characteristic of carriers of Tay-Sachs disease (TSD), while the father suffers from an adult-onset GM2 ganglio-sidosis (AOG) with severe HEX A deficiency. Activity of HEX A in the cultured fetal cells was very low when measured by the heat-inactivation method, thus showing the typical biochemical phenotype of TSD fetuses. However, upon separation of HEX isozymes by ion exchange chromatography, residual HEX A (17 per cent of total HEX) was demonstrated. Also in contrast to TSD fetuses, this fetus' fibroblasts were able to synthesize the precursor of a chains of HEX, and ultrastructural examination of its brain revealed few atypical lamellar bodies, unlike those found in TSD fetuses of the same gestational age. It is therefore concluded that the fetus was not affected with TSD, but rather with AOG.  相似文献   
6.
7.
Environmental Science and Pollution Research - The purpose of this research was evaluation of the effect of soil contamination with waste coming from biomass gasification on chosen indicators of...  相似文献   
8.
In general, tourism plays a significant role in the economy of archipelagos and islands. The Autonomous Region of the Azores has a great potential for tourism, offering multiple attractions, both natural and cultural, creating a big challenge for a sustainable tourism policy since little attention has been paid to the archipelagos and their special needs. This work aims to understand the profile and type of ecotourist that visits the Azores. This knowledge is of great importance for a better management and development of nature-based tourism, and products tailored to the needs and expectations of visitors. The data were collected by means of exit surveys conducted at the Airport of São Miguel Island, the larger and most populated island of the archipelago, during the high tourist season—July–September 2009. The analysis of the visitor’s profile and preferences is crucial to draw adequate strategies of management for tourism, while it helps to adequate the offer to the demand. Results showed that 41.1 % of the tourists claimed to be attracted to the islands due to their “natural values” (e.g., landscape, biodiversity, and geodiversity). The most practiced activities were whale-watching (32.4 %) and mountaineering/hiking (31.6 %), followed by diving (7 %) and other sports (5.1 %). The tourists’ profile points to a mainstream, soft, and incidental type of ecotourist. This information helps to develop and support a strategic planning and management, both at local and regional levels, for sustainable tourism policies.  相似文献   
9.
Environmental Science and Pollution Research - Biodiesel is one among the recent developments in the field of renewable energy research. To enhance the combustion characteristics of compression...  相似文献   
10.
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