全文获取类型
收费全文 | 14577篇 |
免费 | 1171篇 |
国内免费 | 3866篇 |
专业分类
安全科学 | 608篇 |
废物处理 | 206篇 |
环保管理 | 2748篇 |
综合类 | 10364篇 |
基础理论 | 1866篇 |
环境理论 | 8篇 |
污染及防治 | 929篇 |
评价与监测 | 1414篇 |
社会与环境 | 1282篇 |
灾害及防治 | 189篇 |
出版年
2024年 | 105篇 |
2023年 | 355篇 |
2022年 | 579篇 |
2021年 | 653篇 |
2020年 | 704篇 |
2019年 | 594篇 |
2018年 | 523篇 |
2017年 | 660篇 |
2016年 | 681篇 |
2015年 | 764篇 |
2014年 | 783篇 |
2013年 | 1023篇 |
2012年 | 984篇 |
2011年 | 1115篇 |
2010年 | 877篇 |
2009年 | 796篇 |
2008年 | 719篇 |
2007年 | 982篇 |
2006年 | 944篇 |
2005年 | 709篇 |
2004年 | 651篇 |
2003年 | 690篇 |
2002年 | 568篇 |
2001年 | 518篇 |
2000年 | 483篇 |
1999年 | 388篇 |
1998年 | 276篇 |
1997年 | 235篇 |
1996年 | 231篇 |
1995年 | 161篇 |
1994年 | 158篇 |
1993年 | 127篇 |
1992年 | 99篇 |
1991年 | 93篇 |
1990年 | 68篇 |
1989年 | 28篇 |
1988年 | 27篇 |
1987年 | 34篇 |
1986年 | 24篇 |
1985年 | 15篇 |
1983年 | 10篇 |
1982年 | 19篇 |
1981年 | 23篇 |
1980年 | 23篇 |
1979年 | 14篇 |
1978年 | 20篇 |
1977年 | 15篇 |
1975年 | 14篇 |
1972年 | 10篇 |
1971年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
Krzysztof Brzozowski 《Environmental Modeling and Assessment》2006,11(4):371-380
The paper presents a new method of air pollution modelling on a micro scale. For estimation of concentration of car exhaust pollutants, each car is treated as an instantaneous moving emission source. This approach enables us to model time and spatial changes of emission, especially during cold and cool start of an engine. These stages of engine work are a source of significant pollution concentration in urban areas. In this work, two models are proposed: one for the estimation of emission after cold start of the engine and another for the prediction of pollutant concentration. The first model (defined for individual exhaust gas pollutants) enables us to calculate the emission as a function of time after the cold or cool start, ambient temperature and average speed of motion. This model uses the HBEFA database. The second mathematical model is developed in order to calculate the pollutant dispersion and concentrations. The finite volume method is applied to discretise the set of partial differential equations describing wind flow and pollutant dispersion in the domain considered. Models presented in this paper can be called short-term models on a small spatial scale. The results of numerical simulation of pollutant emission and dispersion are also presented. 相似文献
122.
Concentrations of HCB, DDTs and PCBs in the tissues andorgans of cetaceans ( Stenella coeruleoalba, Tursiops truncatus, Balaenoptera physalus, Steno bredanensis}, Grampus griseus} and Globicephala melaena) strandedalong the Italian coasts in the period 1987–1993 are reported. The values are compared between speciesand between specimens of the samespecies. Chlorinated hydrocarbon (CH) levels were found toincrease in relation to the quantity andtype of lipids in each tissue and organ. Differences inaccumulation encountered in the differentspecies are principally due to different feeding habitats.Remarkable differences found between malesand females of each species confirm that during gestation andlactation, females undergo disintoxication by passing much of their total burden of CHs to their young. 相似文献
123.
124.
汽车尾气污染及其净化处理技术 总被引:1,自引:0,他引:1
本文详细阐述了汽车尾气的有害成份及其对人类健康的危害。为此 ,应该采取净化处理措施 ,减少或者消除有害气体的产生 ,为大气环境洁净而创造条件。 相似文献
125.
126.
Land degradation is a consequence stemming from both natural processes and social economic activities. On the bases of analyzing general situation of agricultural land degradation in China, the monetary estimating methods such as market value method and shadow engineering method were used to quantitatively assess the economic loss resulting from land deterioration. Results showed that the economic loss in 1999 was 326.8l billion RMB Yuan, which accounted for 4.1% of GDP in the same year of China. If taking five items namely farmland conversion, soil erosion, salinization, decline in reservoir functions, and siltation in waterways and, comparing with that in 1992, the percentage of economic loss to GDP has increased by 1.5 in the only 7 years. 相似文献
127.
128.
J. Altenburger Th. Dielacher P. Eder H. Ferner M. Fegerl J. Fresner O. Gelinek A. Kogler J. Jantschgi M. Nussbaumer B. Russegger H. Schnitzer K. Schauer B. Sebesta J. Seiler F. Sprenger H. Widenmeyer 《Journal of Cleaner Production》1994,2(3-4)
The paper focuses upon the organization of a federal state-funded pollution prevention project in the Styrian industry. The project includes 13 companies from the textile, pulp and paper, machine building, wood working and printed circuit board manufacturing industries, covering most of the sectors and sizes in the Styrian industry. It started in January 1994 and will last for one year. It will demonstrate the possibilities of pollution prevention and the need for further research work. This project will make use of the methods and tools that were refined in the Austrian Prepare project. As a first step, a systematic balance of all the inputs and outputs of a company is made, after which the weak points and inefficiencies of material and energy use are identified and the options for improvements, both economical and ecological, are defined. Consequently, modifications in products and production lead to a situation with less waste and emissions. The preliminary lessons from these projects are presented: as a rule, the utilities (consumption of process materials and water, cleaning, energy, preparatory and finishing steps) are treated as black boxes and usually represent a considerable optimization potential. In these areas especially there is usually a lack of information and coordination as well as a need for a systematic and comprehensive approach. Leadership in the company and creative consultants are needed for starting lasting successful pollution prevention projects. 相似文献
129.
130.