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   1227篇
  免费   83篇
  国内免费   62篇
安全科学   191篇
废物处理   33篇
环保管理   276篇
综合类   509篇
基础理论   125篇
环境理论   1篇
污染及防治   59篇
评价与监测   47篇
社会与环境   70篇
灾害及防治   61篇
  2024年   3篇
  2023年   8篇
  2022年   24篇
  2021年   44篇
  2020年   49篇
  2019年   24篇
  2018年   26篇
  2017年   44篇
  2016年   47篇
  2015年   46篇
  2014年   62篇
  2013年   90篇
  2012年   101篇
  2011年   95篇
  2010年   73篇
  2009年   61篇
  2008年   53篇
  2007年   86篇
  2006年   68篇
  2005年   51篇
  2004年   62篇
  2003年   35篇
  2002年   34篇
  2001年   22篇
  2000年   36篇
  1999年   24篇
  1998年   18篇
  1997年   16篇
  1996年   8篇
  1995年   3篇
  1994年   4篇
  1993年   11篇
  1992年   4篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   3篇
  1987年   4篇
  1986年   3篇
  1983年   4篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1977年   1篇
  1975年   1篇
  1974年   3篇
  1973年   2篇
  1971年   3篇
  1970年   1篇
  1969年   1篇
排序方式: 共有1372条查询结果,搜索用时 46 毫秒
101.
微波诱导催化技术以其快速、高效和无二次污染等特点,日益受到环保研究者的重视。目前,微波诱导催化技术已在大气污染控制、水污染控制及固体废弃物处理与处置等环境治理领域取得了显著效果。阐述了微波诱导催化技术的基本原理、催化反应的催化剂和载体及催化反应的机制,归纳了微波诱导催化技术在环境治理中的应用现况及实例,分析了微波诱导催化技术在实际应用中存在的问题,并提出相应的解决措施,最后对微波诱导催化技术在环境治理领域中的进一步应用进行了展望。  相似文献   
102.
This paper summarizes a study evaluating the acceptance and perceived performance of disposable cutlery made from starch-based biodegradable resins relative to nondegradable polystyrene cutlery. Two hundred forty-three sailors onboard three U.S. Navy vessels ate their lunch using either biodegradable cutlery made with resins manufactured by one of two commercial companies or polystyrene cutlery. The cutlery was rated on several sensory and performance dimensions as well as for overall acceptability. Results indicated that sailors rated both the biodegradable and the polystyrene utensils as easy to hold. There were also no differences in the perceived ease of using each of the spoons. However, compared to the polystyrene utensils, both types of biodegradable utensils were viewed as less sturdy, as having a less attractive color, and as being less acceptable overall. The biodegradable forks and knives were also rated as more difficult to use for piercing and cutting food than the polystyrene ones. In addition, several significant differences emerged between the two types of biodegradable cutlery. The results are discussed in terms of the need for continued consumer testing of products developed from biodegradable polymeric materials.  相似文献   
103.
We are witnessing a growing concern with the global dimension of many environmental issues, reflected in the increase in the number and significance of international environmental organizations. Yet there is no internationally applicable strategy for environmental research which is management oriented. A new type of research policy, which integrates ideas derived from environmental and human ecology, is required in order to deal with cultural and ecological diversity and their interactions as reflected in the ecology of landscapes. The newly defined concept of environmental health is proposed to fill this gap. This concept integrates the latest developments in landscape evolutionary ecology and environmental health, bringing out a conflict between making the environment conducive to human health and increasing the available options for supporting the essential biological and ecological processes of the environment. Lessons derived from the evolution of human environments are used in order to illustrate how health may become un umbrella for developing an environmental research policy, which could also serve as a catalyst for international environmental projects.  相似文献   
104.
对1224个工种(岗位)的工人接触生产性毒物、粉尘、高温的状况以及部分工种(岗位)的工人体力劳动强度状况进行了调研,初步了解到机械工业的主要职业危害因素、危害分布、危害程度和特征。  相似文献   
105.
ABSTRACT This paper examines the social impact of reservoir construction on a rural community group located in the urban fringe of a major metropolitan area in central Ohio. The study data were collected at three intervals over a ten-year period (1970, 1974, 1980). Evaluation of resident opinions in the affected community revealed significant attitude differences over time for four of the five variables measured. The findings revealed that the study group desired more social stability but had accommodated the changes experienced to date. Responses to the attitude scales showed that the people in the study group were well integrated and were closely identified with each other at all three test periods. Attitudes toward the lake project were significantly more positive over time, and in 1980 the collective community group held a basically neutral attitude about the lake. The development agency was also perceived more positively over time.  相似文献   
106.
107.
The article discusses agricultural practices in sub-Saharan Africa, especially in terms of maintaining soil fertility. It disagrees with alarmist tendencies in the current debate, exaggerating the state of soil impoverishment in the African region. Nor does it subscribe to the idea that the remedy lies primarily in a massive influx of chemical fertilisers, especially phosphorus.
Instead, the article advocates a more balanced approach, where soil nutrient replenishment, as an improvement in natural capital, is but one part of the investment African agriculture needs. To achieve sustainable rural livelihoods, other forms of capital are also required, such as physical capital, i.e. infrastructure (roads, means of communication); financial capital in the form of credit and savings schemes; and human- and social capital, especially improved access to information and knowledge for farmers as well as improved local organisation and empowerment.
The article reviews nine case studies, taken from different climate zones in the region and representing different soil conditions. All case studies were projects using the participatory learning and action research (PLAR) method, which is discussed in detail.  相似文献   
108.
为了探讨火电厂除灰水中的粉煤灰(含炉渣)对炼油厂含碱污水中石油类、COD(cr)等污染物的吸附处理效果,根据某单位现场情况,将炼油厂含碱污水送入火电厂除灰沟→经充分混合排入储灰场→并经长时间沉降分离的流程进行模拟试验,结果表明:由于粉煤灰的吸附作用,显著降低了炼油厂含碱污水中的石油类、COD(cr)、挥发酚、碳化匕物等污染物。  相似文献   
109.
Possible climate change will modify snow-cover depth and change the characteristics of winter tourism and skiing districts. Our model describes seasonal snow-cover depth related to altitude in six Alpine climate regions as the best fit of all snow stations. Data cover 30 winter seasons (November to April values) from 1965 to 1995. We modified the data according to a scenario of temperature and precipitation change (2 °C warming, no precipitation change) and achieve a new simulated snow-cover depth. The indicators MARP (mean altitude of resident population) and MASPSL (mean altitude of starting point of ski lifts) serve as references for “critical altitudes” of Austrian districts. A warming implies a reduction of snow in all districts, but the loss is overproportional in lower altitudes. The direction of economic impacts is clear – income losses and adaptation costs – but magnitude and time frames remain uncertain. Received: 24 February 1999 · Accepted: 15 May 1999  相似文献   
110.
The area of leaves on birch (Betula pubescens ssp. tortuosa) auxiblasts and brachyblasts and the degree of their damage by the complex of leaf-gnawing and leaf-mining insects were studied in a light birch forest. The results showed that phyllophagous insects, primarily snout beetles, prefer young leaves on the apexes of auxiblasts. Thus, selective damage is inflicted on smaller leaves, both on the auxiblasts and in the entire sample. This phenomenon is widespread and may manifest itself in different ways, depending on the pattern of leaf area distribution along the extended shoot and the feeding preferences of the insects. Thus, it is necessary to reconsider research methods and approaches based on the assumption that insects damage leaves nonselectively, irrespective of their size.  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