全文获取类型
收费全文 | 263篇 |
免费 | 34篇 |
国内免费 | 13篇 |
专业分类
安全科学 | 96篇 |
废物处理 | 1篇 |
环保管理 | 33篇 |
综合类 | 75篇 |
基础理论 | 42篇 |
污染及防治 | 4篇 |
评价与监测 | 17篇 |
社会与环境 | 17篇 |
灾害及防治 | 25篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 16篇 |
2020年 | 11篇 |
2019年 | 18篇 |
2018年 | 12篇 |
2017年 | 20篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 16篇 |
2009年 | 16篇 |
2008年 | 8篇 |
2007年 | 18篇 |
2006年 | 7篇 |
2005年 | 13篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 10篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 1篇 |
排序方式: 共有310条查询结果,搜索用时 15 毫秒
111.
It is thought that young homing pigeons are able to use information acquired en route for their initial homeward orientation. However, the cues involved and mechanisms utilised are under discussion. Blocking light-dependent route-specific information during the first leg of an outward journey detour, together with analysis of pigeons that were raised under different loft conditions, allowed us to correctly evaluate the functioning of this mechanism and, more generally, the navigational map of birds. Pigeons from the same stock were raised and kept in two different lofts. The birds in the experimental groups were transported to the release sites via detours, and light-dependent information was denied during the first half of the outward journey (no compass information was available). Control birds were transported by the most direct route and had access to all available information. In general, the results showed that the low-loft birds preferred to use magnetic compass cues, whereas the high-loft birds preferred to use navigational map cues to collect information of the first part of the outward journey. The impairments observed in the homing performances of the experimental groups highlight the reliability of information collected inside the map area. Relevant to an understanding of the route-reversal mechanism was the evidence that this mechanism is able to function in the absence of compass information (birds raised in a wind-exposed loft show a detour effect). In systems where directional information could be provided by multiple sources, processing and extracting accurate course trajectories through a common mechanism may prove more efficient and reliable. 相似文献
112.
113.
114.
115.
工作底图的编制是开展抗震规划的基础工作之一,好的工作底图不仅能突出抗震规划专题信息,更有利于规划成果的应用。本文以1∶5 000地形图缩编成1∶5万抗震规划工作底图为例,分析了规划底图缩编过程中存在的问题,探索了基于AutoCAD、南方Cass软件以及Arcgis的缩编方法,从而有效提高抗震规划的工作效率。 相似文献
116.
117.
Robyn Kruk ;Derek Thompson ;Jiyuan Liu ;Xiangzheng Deng ;Peishen Wang 《中国人口.资源与环境(英文版)》2013,11(3):244-252
China has made some remarkable achievements in sustainable development,but the constant deterioration of the overall trend of the environment has not yet been effectively curbed.To achieve the goal of sustainable development,we must first ensure coordination and coherence of national development goals in different areas and adhere to green development road.To achieve the objectives related to green development,and to clarify the direction of green development in the next 20years,a road map is needed to guide and coordinate the process.This paper describes the concept of the green development road map,introduces a green development road map for the western region,and further elaborates it The road map clarifies the objectives and guiding principles of green development in the western region,points the areas that deserve more concern and institutional innovation,and builds a green development monitoring and evaluation(M&E)framework.Finally,the paper provides corresponding policy recommendations based on the established road map. 相似文献
118.
为充分发挥商场工作人员在火灾风险下的疏导作用,提高疏散效率。引入火灾安全意识、行为选择动机、火灾认知能力为中介变量,研究商场工作人员自我效能感与火灾时的有利行为、不利行为之间的关系,构建结构方程模型;对西安市某大型商场212名工作人员进行问卷调查,运用Amos24.0软件进行分析。研究结果表明:自我效能感主要通过火灾安全意识、行为选择动机、火灾认知能力对商场工作人员发生火灾时的行为产生影响,这3个中介变量对商场工作人员发生火灾时的有利行为呈显著正相关,对不利行为呈显著负相关;火灾认知能力对商场工作人员发生火灾时的有利行为影响最大,行为选择动机对商场工作人员发生火灾时的不利行为影响最大。研究结果可为商场火灾安全疏散管理提供有效依据,对商场火灾疏散具有重要意义。 相似文献
119.
120.