全文获取类型
收费全文 | 1478篇 |
免费 | 196篇 |
国内免费 | 134篇 |
专业分类
安全科学 | 255篇 |
废物处理 | 14篇 |
环保管理 | 340篇 |
综合类 | 604篇 |
基础理论 | 208篇 |
污染及防治 | 34篇 |
评价与监测 | 158篇 |
社会与环境 | 103篇 |
灾害及防治 | 92篇 |
出版年
2024年 | 5篇 |
2023年 | 31篇 |
2022年 | 59篇 |
2021年 | 81篇 |
2020年 | 64篇 |
2019年 | 66篇 |
2018年 | 50篇 |
2017年 | 81篇 |
2016年 | 105篇 |
2015年 | 60篇 |
2014年 | 66篇 |
2013年 | 96篇 |
2012年 | 90篇 |
2011年 | 109篇 |
2010年 | 73篇 |
2009年 | 88篇 |
2008年 | 56篇 |
2007年 | 102篇 |
2006年 | 74篇 |
2005年 | 56篇 |
2004年 | 51篇 |
2003年 | 48篇 |
2002年 | 43篇 |
2001年 | 29篇 |
2000年 | 37篇 |
1999年 | 18篇 |
1998年 | 20篇 |
1997年 | 25篇 |
1996年 | 16篇 |
1995年 | 9篇 |
1994年 | 15篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1983年 | 4篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1971年 | 3篇 |
1970年 | 1篇 |
排序方式: 共有1808条查询结果,搜索用时 578 毫秒
981.
产品包装对产品流通的安全保障有至关重要的作用,为了检测产品包装的抗跌落效果,需要对产品进行包装跌落测试。本文从如何利用数据冲击采集分析系统在产品包装跌落试验中得到的测试数据,合理的有针对性的改进产品包装设计,以达到节约包装设计的时间和成本,提高产品流通安全性的目的。 相似文献
982.
Andrea Báez Montenegro Mario Niklitschek Huaquin Luis César Herrero Prieto 《Journal of Environmental Planning and Management》2009,52(1):97-109
The economic valuation of cultural heritage is an area of increasing interest and an important research topic in the emerging field of cultural economics. Many services and values associated with cultural heritage are not traded in markets, and their estimation requires methods developed for the valuation of non-market goods, such as those used in environmental economics. This paper applies the contingent valuation method with double dichotomous choice to estimate the value of historical sites in the city of Valdivia, Chile. The valuation exercise was implemented by designing a hypothetical guided walking tour to a cluster of historical sites in the city centre, and surveying tourists visiting the city during the summer of 2004. Parametric and non-parametric statistical methods were used to estimate the survival distribution and the mean and median estimates of the willingness-to-pay (WTP). The study emphasizes the importance of explicitly treating heterogeneous preferences and the sensitivity of the survival distribution to the estimation methods used. 相似文献
983.
浅论环境监测数据的综合分析方法 总被引:4,自引:0,他引:4
叶萍 《中国环境管理干部学院学报》2009,19(1):99-101
准确、可靠、可比的环境监测数据是环境科学研究工作的基础,是环境管理的依据。在第一时间判断出监测分析数据是否合理的基础上,再对监测分析的数据作进一步的分析评价,是整个数据综合分析的基础,为进一步综合分析数据提供了依据。本文通过分析几种常用的监测数据的分析方法,说明对监测数据进行综合分析是至关重要的。 相似文献
984.
Landscape-climatic changes on the eastern macroslope of the Northern Urals over the past 50000 years
E. G. Lapteva 《Russian Journal of Ecology》2009,40(4):267-273
Landscape-climatic changes are described that took place in the second half of the Late Neopleistocene and Holocene on the eastern macroslope of the Northern Urals. On the basis of geochronological and palynological data, the composition of paleocommunities in different time sections over the past 50000 years has been reconstructed in detail. Paleoclimatic parameters calculated by the zonal-formation method are presented. 相似文献
985.
提出了林火遥感图像挖掘的概念,描述了图像挖掘技术在林火遥感图像上的具体应用及实现,针对林火部门每天产生并存储的有价值的林火遥感图像,结合林火上所特有的领域知识,提出了一种通过对林火遥感图像进行图像挖掘,可以将林火遥感图像分成有火或无火两类图像的方法。该方法的实现对帮助林火工作人员及早发现火情,做出火灾预测并采取相应措施具有重大的意义。 相似文献
986.
高危作业预警计算机系统设计 总被引:6,自引:2,他引:4
为了利用计算机技术对高危作业有害因素的预防控制水平进行动态评估和预警,在对现有的安全预警系统进行分析总结的基础上,根据高危作业的特点,给出了高危作业预警系统的设计方案. 相似文献
987.
基于有界数据包络分析(DEA)模型的应急避难场所效率评价 总被引:2,自引:2,他引:0
应用数据包络分析(DEA)方法,针对应急避难场所规划建设和运营维护两种情况,分别建立以建设成本和运营成本为输入指标,以服务性、可达性、安全性为输出指标的效率评价指标体系,并选择有界DEA模型,分层次对应急避难场所的投入产出效率进行评价。实证案例表明,临时和中长期避难场所比短期避难场所更容易获得较高的DEA效率;位于区域内部、交通便利的应急避难场所DEA效率较高;提高应急避难场所的综合利用水平,更有利于提高其DEA效率。 相似文献
988.
Introduction
In this paper, we show that FARS data can be a comparable alternative to observational NOPUS data in estimating seat belt use in the United States once we correct for sample selection bias.Results
Based on assumptions of independence for seatbelt choice, we establish a lower and upper bound for seatbelt usage rates, and find that once we correct for sample selection bias, the seatbelt usage estimates from the corrected FARS emerge at least as a comparable alternative to NOPUS estimates.Impact on Industry
This implies that researchers can use corrected FARS to complement NOPUS, thus being able to utilize the rich cross-sectional details available in FARS data to analyze various relevant research questions. 相似文献989.
The USGS Water Availability and Use Science Program: Needs,Establishment, and Goals of a Water Census
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ari M. Michelsen Sonya Jones Eric Evenson David Blodgett 《Journal of the American Water Resources Association》2016,52(4):836-844
Many reports have recognized the need for a national water census for the United States and have called upon the U.S. Geological Survey to undertake this challenge. For example, the National Science and Technology Council stated: “The United States has a strong need for an ongoing census of water that describes the status of our Nation's water resource at any point in time and identifies trends over time.” Responding to the need for this information, the U.S. Congress established the SECURE Water Act. The directives are to provide a more accurate assessment of the status of the water resources of the United States; determine the quantity of water available for beneficial uses; identify long‐term trends in water availability; assist in determination of the quality of the water resources; and develop the basis for an improved ability to forecast the availability of water for future economic, energy production, and environmental uses. This article provides summary and new information on the process and progress on work to estimate water budget components nationwide, involvement of stakeholder interests, efforts to examine water‐use characteristics throughout the Nation, studies of water availability in geographically focused areas and the initiation of methods to provide open access to existing and new water resources information contributing to Open Water Data Initiative (OWDI) efforts and objectives. 相似文献
990.
A Multi‐Scale Analysis of Low‐Rise Apartment Water Demand through Integration of Water Consumption,Land Use,and Demographic Data
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Saeed Ghavidelfar Asaad Y. Shamseldin Bruce W. Melville 《Journal of the American Water Resources Association》2016,52(5):1056-1067
Over the past decades, multi‐unit housing developments have been vastly expanded across urban areas due to the population growth. To properly supply water to this growing sector, it is essential to understand the determinants of its water use. However, this task has largely remained unexplored through the empirical study of water demand mainly due to the scarcity of data in this sector. This study integrated apartment water consumption, property characteristics, weather, water pricing, and census microdata to overcome this issue. Using a rich source of GIS‐based urban databases in Auckland, New Zealand, the study developed a large dataset containing the information of 18,000 low‐rise apartments to evaluate the determinants of water use both in the household scale and aggregated scale. The household‐scale demand analysis helped to assess the heterogeneity in responses to the demand drivers specifically water price across different consumer groups, whereas the aggregated analysis revealed the determinants behind the spatial variation in water demand at the census area unit level. Through applying panel data models, the study revealed the household size as the most important determinant of apartment water use in Auckland, where other socioeconomic factors, building features, and water pricing were not significant determinants. This knowledge of determinants of water demand can help water planners to better manage water demand in the compact urban environments. 相似文献