全文获取类型
收费全文 | 14141篇 |
免费 | 1347篇 |
国内免费 | 3041篇 |
专业分类
安全科学 | 2469篇 |
废物处理 | 375篇 |
环保管理 | 2481篇 |
综合类 | 7482篇 |
基础理论 | 1821篇 |
环境理论 | 16篇 |
污染及防治 | 1326篇 |
评价与监测 | 1063篇 |
社会与环境 | 859篇 |
灾害及防治 | 637篇 |
出版年
2024年 | 60篇 |
2023年 | 274篇 |
2022年 | 493篇 |
2021年 | 582篇 |
2020年 | 536篇 |
2019年 | 562篇 |
2018年 | 500篇 |
2017年 | 601篇 |
2016年 | 746篇 |
2015年 | 716篇 |
2014年 | 829篇 |
2013年 | 1097篇 |
2012年 | 1167篇 |
2011年 | 1305篇 |
2010年 | 888篇 |
2009年 | 1017篇 |
2008年 | 762篇 |
2007年 | 927篇 |
2006年 | 834篇 |
2005年 | 709篇 |
2004年 | 528篇 |
2003年 | 507篇 |
2002年 | 427篇 |
2001年 | 348篇 |
2000年 | 288篇 |
1999年 | 282篇 |
1998年 | 193篇 |
1997年 | 195篇 |
1996年 | 180篇 |
1995年 | 156篇 |
1994年 | 142篇 |
1993年 | 106篇 |
1992年 | 90篇 |
1991年 | 63篇 |
1990年 | 49篇 |
1989年 | 40篇 |
1988年 | 46篇 |
1987年 | 27篇 |
1986年 | 18篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 16篇 |
1982年 | 29篇 |
1981年 | 21篇 |
1980年 | 21篇 |
1979年 | 20篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1972年 | 18篇 |
1971年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
771.
Luyao Wen Chun Yang Xiaoliang Liao Yanhao Zhang Xuyang Chai Wenjun Gao Shulin Guo Yinglei Bi Suk-Ying Tsang Zhi-Feng Chen Zenghua Qi Zongwei Cai 《环境科学学报(英文版)》2022,34(5):443-452
The COVID-19 pandemic has raised awareness about various environmental issues,including PM2.5 pollution.Here,PM2.5 pollution during the COVID-19 lockdown was traced and analyzed to clarify the sources and factors influencing PM2.5 in Guangzhou,with an emphasis on heavy pollution.The lockdown led to large reductions in industrial and traffic emissions,which significantly reduced PM2.5 concentrations in Guangzhou.Interestingly,the trend of PM2.5 相似文献
772.
773.
运用多元回归法,通过预测模型的选择、数学模型的建立、基础数据的整理和回归效果的检验,建立环境污染范围与诸条件的关系,达到快速估算的目的,从而形成一种有效的大气环境污染事故范围预测的方法. 相似文献
774.
775.
湿法烟气脱硫是成熟且具有较好发展前景的工艺,其中关键是对脱硫塔的选择及通过各项参数的控制达到良好的脱硫效率.通过对脱硫塔酸碱度(PH)、气液比(L/G)、流场特性、结垢等各种性能进行分析研究,对脱硫塔的选择和实际运行具有一定的指导意义. 相似文献
776.
对Ni/Fe二元金属表面特性、在氯代有机物还原脱氯中的应用以及还原机理的研究概况进行了综述,并讨论了实际应用中存在的问题和发展前景. 相似文献
777.
778.
通过计算43种有机磷农药的各种结构参数,运用多元线性回归分析方法比较了适用于有机磷农药色谱保留值的定量关系表达式,建立了有机磷农药结构参数对色谱保留值的QSPR模型.模型分析表明:磷酸酯与硫逐磷酸酯两类有机磷农药的模型非交叉验证相关系数R2分别为0.991和0.998,标准误差SE分别为0.0539和0.2874,交叉验证相关系数Q2分别为0.976和0.990,标准偏差Scv分别为0.086和0.610.在已知磷酸酯与硫逐磷酸酯两类有机磷农药结构参数的情况下,此模型可有助于有机磷农药的色谱分析. 相似文献
779.
Bryan BA 《Environmental management》2006,37(1):126-140
The desire to capture natural regions in the landscape has been a goal of geographic and environmental classification and ecological land classification (ELC)
for decades. Since the increased adoption of data-centric, multivariate, computational methods, the search for natural regions
has become the search for the best classification that optimally trades off classification complexity for class homogeneity.
In this study, three techniques are investigated for their ability to find the best classification of the physical environments
of the Mt. Lofty Ranges in South Australia: AutoClass-C (a Bayesian classifier), a Kohonen Self-Organising Map neural network,
and a k-means classifier with homogeneity analysis. AutoClass-C is specifically designed to find the classification that optimally
trades off classification complexity for class homogeneity. However, AutoClass analysis was not found to be assumption-free
because it was very sensitive to the user-specified level of relative error of input data. The AutoClass results suggest that
there may be no way of finding the best classification without making critical assumptions as to the level of class heterogeneity
acceptable in the classification when using continuous environmental data. Therefore, rather than relying on adjusting abstract
parameters to arrive at a classification of suitable complexity, it is better to quantify and visualize the data structure
and the relationship between classification complexity and class homogeneity. Individually and when integrated, the Self-Organizing
Map and k-means classification with homogeneity analysis techniques also used in this study facilitate this and provide information
upon which the decision of the scale of classification can be made. It is argued that instead of searching for the elusive
classification of natural regions in the landscape, it is much better to understand and visualize the environmental structure
of the landscape and to use this knowledge to select the best ELC at the required scale of analysis. 相似文献
780.
TUGAI: An Integrated Simulation Tool for Ecological Assessment of Alternative Water Management Strategies in a Degraded River Delta 总被引:1,自引:0,他引:1
Schlüter M Rüger N Savitsky AG Novikova NM Matthies M Lieth H 《Environmental management》2006,38(4):638-653
The development of ecologically sound water allocation strategies that account for the needs of riverine ecosystems is a pressing
issue, especially in semiarid river basins. In the Aral Sea Basin, a search for strategies to mitigate ecological and socioeconomic
deterioration has been in process since the early 1990s. The Geographic Information System–based simulation tool TUGAI has
been developed to support the policy determination process by providing a simple, problem-oriented method to assess ecological
effects of alternative water management strategies for the Amudarya River. It combines a multiobjective water allocation model
with simple, spatially explicit statistical and rule-based models of landscape dynamics. Changes in environmental conditions
are evaluated by a fuzzy habitat suitability index for Populus euphratica, which is the dominant species of the characteristic riverine Tugai forests. Water management scenarios can be developed
by altering spatiotemporal water distribution in the delta area or the amount of water inflow into the delta. Outcomes of
scenario analysis are qualitative comparisons of the ecological effects of different options for a time period of up to 28
years. The given approach utilizes different types of knowledge, from quantitative hydrological data to qualitative local
expert knowledge. The main purpose of the tool is to integrate the knowledge in a comprehensive way to make it available for
discussions on alternative policies in moderated workshops with stakeholders. In this article, the modules of the tool, their
integration, and three hypothetical scenarios are presented. Based on the experience gained when developing the TUGAI tool,
we propose that the general framework can be transferred to other areas where tradeoffs in water allocation between the environment
and other water users are of major concern. The potential for a simulation tool to structure and inform a complex resource
management situation by involving local experts and stakeholders in the development of possible future scenarios will become
increasingly valuable for transparent and participatory resource management. 相似文献