全文获取类型
收费全文 | 1277篇 |
免费 | 36篇 |
国内免费 | 49篇 |
专业分类
安全科学 | 258篇 |
废物处理 | 15篇 |
环保管理 | 242篇 |
综合类 | 576篇 |
基础理论 | 48篇 |
环境理论 | 1篇 |
污染及防治 | 41篇 |
评价与监测 | 35篇 |
社会与环境 | 59篇 |
灾害及防治 | 87篇 |
出版年
2023年 | 7篇 |
2022年 | 12篇 |
2021年 | 28篇 |
2020年 | 63篇 |
2019年 | 20篇 |
2018年 | 10篇 |
2017年 | 23篇 |
2016年 | 31篇 |
2015年 | 53篇 |
2014年 | 69篇 |
2013年 | 71篇 |
2012年 | 97篇 |
2011年 | 127篇 |
2010年 | 81篇 |
2009年 | 80篇 |
2008年 | 41篇 |
2007年 | 84篇 |
2006年 | 78篇 |
2005年 | 58篇 |
2004年 | 48篇 |
2003年 | 57篇 |
2002年 | 36篇 |
2001年 | 42篇 |
2000年 | 32篇 |
1999年 | 24篇 |
1998年 | 16篇 |
1997年 | 16篇 |
1996年 | 16篇 |
1995年 | 10篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1362条查询结果,搜索用时 526 毫秒
891.
粉尘爆炸技术的最新发展 总被引:7,自引:0,他引:7
系统论述了爆炸防护技术的最新发展,为了选择最佳防护措施必须恰当鉴定和评估,包括材料的性质。借助一些经验公式,可估算温度对各种材料操作参数的影响。用情化法不仅可防止可爆混合物的形成还可防止其着火。对设备的“结构防爆”措施,近年来已制造出买用的容器。可以确信,工业爆炸防护领域必将拥有足够的技术以有效地战胜爆炸危险。 相似文献
892.
上海国际航运中心建设目标和战略举措研究 总被引:1,自引:1,他引:0
沈玉芳 《长江流域资源与环境》1999,8(4):345-352
国际航运中心是指以国际航运、国际贸易、国际金融为主要依托的港口城市,也是国际贸易、全球生产分工、商品流通和资源分配的枢纽。从21世纪中国经济发展的需要、上海实现“一个龙头、三个中心”的实际要求以及国际航运市场的竞争态势出发,上海必须在21世纪初建设成为国际航运中心。 相似文献
893.
ABSTRACT: Recent Federal and some State legislation has enlarged the scope of permitted or required actions of local units of government in water resources management and protection. Much of the legislation encourages local units of government to introduce water resources planning measures which will be preventive instead of corrective. Extensive public works measures, environmental destruction and the threat to human life can thus be eliminated or reduced. Research has developed and tested a method for identifying the elements of a water resources protection program for small urbanizing watersheds which was technically adequate and socially acceptable to the communities implementing such programs. Research results suggest that deliberate efforts will be necessary to inform and educate local units of government as to the usefulness of the legislation; and that the program must reflect local natural resource conditions and local preferences for the method of accomplishing the protection. Successful implementation could be restrained by inertia of local units of government, a lack of tradition in such programs, and hostile existing agencies. 相似文献
894.
William K. Johnson Darryl W. Davis 《Journal of the American Water Resources Association》1984,20(1):15-22
ABSTRACT: The Hydrologic Engineering Center, Corps of Engineers, has been engaged in research, training, and project assistance in non-structural flood control planning for Corps offices across the United States since 1975. Lessons learned from this experience deal with the role of nonstructural measures in flood plain management, the role of creativity in analysis, the role of analysis, and tools for analysis. The role of nonstructural measures in flood control planning depends upon the scale of the problem, the nature of the measure, the degree of protection desired, and whether damage is to existing or future property. An earnest seeking for nonstructural opportunities, a field presence for their formulation, and compatbility with local infrastructure plans are prerequisite to creative use of nonstructural measures. Analysis is a necessary complement of creativity. Several tools for nonstructural analysis have been developed and applied to flood problems involving several hundred and several thousand structures. 相似文献
895.
896.
言语训依据详细的资料,阐明了我国水污染现状的严重性,分析了其产生原因,为了使我国水环境避免走“先污染,后治理”的西方老路,文中提出了综合的控制措施。 相似文献
897.
James Damsere-Derry Beth E. Ebel Charles N. Mock Francis Afukaar Peter Donkor Thomas Ojo Kalowole 《Traffic injury prevention》2019,20(3):336-342
Objectives: Each year, pedestrian injuries constitute over 40% of all road casualty deaths and up to 60% of all urban road casualty deaths in Ghana. This is as a result of the overwhelming dependence on walking as a mode of transport in an environment where there are high vehicular speeds and inadequate pedestrian facilities. The objectives of this research were to establish the (1) impact of traffic calming measures on vehicle speeds and (2) association between traffic calming measures and pedestrian injury severity in built-up areas in Ghana.Method: Vehicle speeds were unobtrusively measured in 38 selected settlements, including 19 with traffic calming schemes and 19 without. The study design used in this research was a matched case–control. A regression analysis compared case and control casualties using a conditional logistic regression.Results: Generally, the mean vehicle speeds and the proportion of vehicles exceeding the 50?km/h speed limit were significantly lower in settlements that have traffic calming measures compared to towns without any traffic calming measures. Additionally, the proportion of motorists who exceeded the speed limit was 30% or less in settlements that have traffic calming devices and the proportion who exceeded the speed limit was 60% or more in towns without any traffic calming measures. The odds of pedestrian fatality was significantly higher in settlements that have no traffic calming devices compared to those that have (odds ratio [OR]?=?1.98; 95% confidence interval, 1.09–4.43). The protective effects of a traffic calming scheme that has a speed table was notably higher than those where there were no speed tables.Conclusion: It was clearly evident that traffic calming devices reduce vehicular speeds and, thus, the incidence and severity of pedestrian injuries in built-up areas in Ghana. However, the fact that they are deployed on arterial roads is increasingly becoming a road safety concern. Given the emerging safety challenges associated with speed calming measures, we recommend that their use be restricted to residential streets but not on arterial roads. Long-term solutions for improving pedestrian safety proposed herein include bypassing settlements along the highways to reduce pedestrians’ exposure to traffic collisions and adopting a modern way of enforcement such as evidence-based laser monitoring in conjunction with a punishment regime that utilizes the demerit points system. 相似文献
898.
899.
通过对某钢铁厂2014年发生的事故统计分析,找出事故发生的主要规律和原因,提出预防事故重复发生的措施,达到减少或杜绝事故发生,确保安全生产。 相似文献
900.
2014年APEC会议期间北京市空气质量分析 总被引:6,自引:2,他引:4
为研究区域性大气污染物减排措施对北京市空气质量的影响,结合地面观测的气象数据、能见度、常规污染物浓度和PM2.5化学组分,对APEC会议期间北京市的空气质量进行分析.结果表明,APEC期间的11月4日和8-10日两个过程,大气污染物扩散条件较不利,易出现污染过程.APEC期间,密云、榆垡、昌平、奥体中心和西直门北大街5个站点SO2、NO2、O3、PM10和PM2.5平均浓度分别为(8.0±8.0)、(37.4±21.6)、(36.0±22.5)、(67.7±43.4)和(48.6±42.2) μg·m-3.与近5年同期(PM2.5为去年同期)相比,SO2、NO2、PM10和PM2.5日均浓度分别下降了61.5%、40.8%、36.4%和47.1%,O3日均浓度上升了101.8%.从污染物日变化规律来看,减排措施的环境效果在大气污染物扩散条件较有利的时段体现的更明显.在APEC期间,PM2.5浓度在前半夜保持平稳,未出现积累峰值.与秋季非APEC期间相比,PM2.5中大部分组分浓度均有明显下降,二次离子组分降幅尤为明显.同时,本文测算了APEC期间减排措施的"净环境效益",发现减排措施使得SO2、NO2、PM10和PM2.5浓度分别降低了74.1%、48.0%、66.6%和64.7%,O3浓度上升了189.2%.与10月份的大气污染过程相比,同样在不利气象条件下,实施减排措施后PM2.5浓度峰值明显降低,积累速度明显减缓. 相似文献