全文获取类型
收费全文 | 894篇 |
免费 | 55篇 |
国内免费 | 48篇 |
专业分类
安全科学 | 137篇 |
废物处理 | 19篇 |
环保管理 | 94篇 |
综合类 | 235篇 |
基础理论 | 396篇 |
污染及防治 | 30篇 |
评价与监测 | 30篇 |
社会与环境 | 40篇 |
灾害及防治 | 16篇 |
出版年
2023年 | 5篇 |
2022年 | 11篇 |
2021年 | 15篇 |
2020年 | 21篇 |
2019年 | 11篇 |
2018年 | 10篇 |
2017年 | 24篇 |
2016年 | 28篇 |
2015年 | 21篇 |
2014年 | 26篇 |
2013年 | 35篇 |
2012年 | 44篇 |
2011年 | 56篇 |
2010年 | 54篇 |
2009年 | 54篇 |
2008年 | 73篇 |
2007年 | 78篇 |
2006年 | 83篇 |
2005年 | 59篇 |
2004年 | 51篇 |
2003年 | 33篇 |
2002年 | 19篇 |
2001年 | 19篇 |
2000年 | 24篇 |
1999年 | 30篇 |
1998年 | 21篇 |
1997年 | 20篇 |
1996年 | 20篇 |
1995年 | 18篇 |
1994年 | 12篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有997条查询结果,搜索用时 0 毫秒
271.
在痕量分析中,为获得准确的分析结果,容量材质以及洗涤方法的选择至关重要。试验分析表明:聚乙烯是较好的容器材料,它玷污最小、易洗涤、价廉、容器清洗。经实验证明:蒸汽法效果好,但需要相应装置;浸泡法简单易行,但消耗较大。其他方法则各有利弊,因此可根据不同的分析元素及特征,选择合适的洗涤方法。 相似文献
272.
论企业安全文化建设途径 总被引:6,自引:1,他引:6
黄煌辉 《中国安全科学学报》2002,12(1):23-25
着重从提高企业决策层、管理层、操作层的安全文化素质的观点 ,论述和探讨企业安全文化建设的主要方法和途径。 相似文献
273.
污泥脱水机械的选择讨论 总被引:4,自引:0,他引:4
CaSO4沉淀污泥的脱水因化学性质的特殊性,在脱水机械的选用上应考虑一些影响其脱水的因素,对部分影响因素作一些探讨。 相似文献
274.
DUAN Guang-ming ZHAO Jing-zhu LIU Guo-hu KE Bing XIAO Han WU Gang DENG Hong-bing 《环境科学学报(英文版)》2004,16(2):308-315
This paper assess the eco-environmental benefits that may come from the middle route project of China‘s South-North Water Transfer Scheme(SNWT) with principles and methods of eco-economics and planning reports of SNWT‘s middle route project. Some benefits were calculated in monetary units. To make sure that the results can be comparable with normal monetary indices, concrete assessment objects and the parameters are prudently selected according to the major characteristics of the project and its water import region. Primary assessment revealed that in different project construction stages, the benefit could be more than 13.07 billion RMB Yuan in 2010 and 19.79 billion RMB Yuan in 2030, respectively. The monetary value tends to increase with social-economic development. To realize these potential benefits, however, calls for more endeavors. 相似文献
275.
276.
In this case study of a degraded tropical landscape, we examine how the protected area system in Hong Kong, China, should be modified to improve its efficiency in protecting the surprisingly rich biota. The challenge lies in the fine scale of site selection, and the absence of a core area with high species richness and rarity. Site selection was first conducted in 1 km grid units by selecting hotspots and irreplaceable sites using field records for eight groups of species (amphibians, reptiles, mammals, breeding birds, ants, butterflies, dragonflies and rare vascular plants). The habitats of conservation value within the selected grid units were then delineated on the basis of expert knowledge. Recommendations for increasing the total existing protected area by 6% (i.e. an additional 2% of Hong Kong's total land area) were submitted to the Government in August 2000. To test the robustness of the results, site selection was repeated in 2001 using updated data and different selection methods. The numbers of squares selected by complementarity-based algorithms were similar to those by the hotspots and irreplaceable site method. Sites selected for rare species were very sensitive to data completeness, implying that the application of complementarity-based algorithms at fine scales might be limited. 相似文献
277.
Mrosovsky N 《Environmental management》2006,38(4):703-531
Sea turtles have a high reproductive output and high mortality at early stages of the life cycle. In particular, many nests
are laid below or close to high tide lines, and subsequently large numbers of eggs may be inundated and destroyed. A common
conservation procedure is to relocate such doomed eggs to higher ground. This article examines this practice in the light
of recent data revealing that some individual turtles tend to nest relatively near the water and others relatively higher
up the beach. Discussion is focused on the question of why apparently poor placement of nests has not been selected against.
Comparison between the ecology of leatherback and hawksbill turtle nesting beaches suggests that predictability of environmental
conditions on the nesting beaches has an important influence on patterns of nest-site selection. Options are outlined for
the management of nesting beaches where a high proportion of turtle eggs is subject to destruction by flooding.
An erratum to this article is available at. 相似文献
278.
为合理选择应急物流配送中心地址,提高应急管理能力,基于地震灾害风险评价数据,通过ArcGIS平台形成Voronoi图,可视化表达地震应急准备分区方案并进行应急物流中心预选址;在考虑需求权重情况下,构建应急物流配送中心优化选址模型,通过LINGO软件编程求解得出基于震灾应急准备分区的应急物流配送中心选址方案,并以A市为例,通过与传统行政区划建设方案进行对比,验证本文选址方案的有效性。研究结果表明:本文选址优化模型综合考虑各方面因素,使服务里程总量减少31.39%,单位服务量提高30.61%,验证选址方案的配送效率与公平性。 相似文献
279.
280.
关键基础设施(CI)是维持社会大系统正常运行的重要组成部分,是复杂的网络巨系统,而CI抗灾能力评估指标需具有系统性、客观性和一致性。案例驱动与数据驱动在能力评估指标选择中各有优势,亦相互支持。依靠案例驱动,可以把握历史经验,引导CI抗灾能力评估的情景设计及全局指标选择改进;借助数据驱动,可以发现潜在的微观指标,通过数据分析引导抗灾能力评估微观指标体系改进与完善。集成这2种评估驱动方法,提出CI抗灾能力评估指标选择的案例-数据集成驱动框架,并结合用例验证评估方法的有效性。 相似文献