全文获取类型
收费全文 | 34349篇 |
免费 | 446篇 |
国内免费 | 512篇 |
专业分类
安全科学 | 1172篇 |
废物处理 | 1584篇 |
环保管理 | 4682篇 |
综合类 | 5498篇 |
基础理论 | 9023篇 |
环境理论 | 25篇 |
污染及防治 | 8848篇 |
评价与监测 | 2324篇 |
社会与环境 | 1921篇 |
灾害及防治 | 230篇 |
出版年
2023年 | 182篇 |
2022年 | 360篇 |
2021年 | 363篇 |
2020年 | 291篇 |
2019年 | 337篇 |
2018年 | 583篇 |
2017年 | 585篇 |
2016年 | 877篇 |
2015年 | 666篇 |
2014年 | 1019篇 |
2013年 | 2749篇 |
2012年 | 1240篇 |
2011年 | 1681篇 |
2010年 | 1332篇 |
2009年 | 1396篇 |
2008年 | 1631篇 |
2007年 | 1696篇 |
2006年 | 1430篇 |
2005年 | 1260篇 |
2004年 | 1126篇 |
2003年 | 1184篇 |
2002年 | 1066篇 |
2001年 | 1304篇 |
2000年 | 945篇 |
1999年 | 571篇 |
1998年 | 407篇 |
1997年 | 407篇 |
1996年 | 407篇 |
1995年 | 490篇 |
1994年 | 511篇 |
1993年 | 402篇 |
1992年 | 423篇 |
1991年 | 387篇 |
1990年 | 415篇 |
1989年 | 376篇 |
1988年 | 321篇 |
1987年 | 315篇 |
1986年 | 257篇 |
1985年 | 279篇 |
1984年 | 302篇 |
1983年 | 298篇 |
1982年 | 287篇 |
1981年 | 259篇 |
1980年 | 201篇 |
1979年 | 209篇 |
1978年 | 202篇 |
1977年 | 131篇 |
1975年 | 147篇 |
1972年 | 135篇 |
1971年 | 138篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
321.
V. M. Emets 《Russian Journal of Ecology》2016,47(4):371-375
The role of ecotones with different (sharp or smooth) spatial boundaries between forest and meadow in ant biodiversity preservation was studied at the right-of-way of a power line in the Voronezh Reserve. The ecotone with a sharp boundary between forest and meadow (transitional zone 2 m wide) had higher species richness of ants compared to the ecotones (also 2 m wide) with smooth boundary between forest and meadow. 相似文献
322.
N. P. Korablev M. P. Korablev P. N. Korablev I. L. Tumanov 《Russian Journal of Ecology》2016,47(3):289-295
A comparative analysis of epigenetic variation has been performed in nine European populations and population groups of the American mink. It has been shown that differentiation of samples in nonmetric characters is due mainly to endogenous processes that have occurred in introduced populations in the course of colonization of new territory by the invasive species. Environmental factors have played a secondary role, with the influence of the geographic (latitudinal) origin of a given sample being considerable and stronger than that of macroclimatic factors. 相似文献
323.
S. Alvandi W. Li M. Schönemann C. Herrmann 《International Journal of Sustainable Engineering》2016,9(6):354-362
Value stream mapping (VSM) is a well-accepted tool within lean manufacturing concept which is often used for analysing and designing the flow of materials and information required to manufacture a product. However, the analysis is static and single product oriented, which fails to cope with either the variation of production plan or a multi-product environment. In addition, the environmental impact of a manufacturing system is highly associated with the dynamic consumption of energy and resources. Despite the recent integration of VSM with simulation or environmental studies (in the domain of energy efficiency), still neglected is the dynamic assessment of all the resources involved in a multi-product production environment. This paper presents a methodology for modelling multi-product manufacturing systems with dynamic material, energy and information flows with the aim to generate economic and environmental value stream maps (E2VSM). The proposed methodology is validated with an industrial case. 相似文献
324.
An analysis is made of the spatial variability of snowmelt water composition (within and between biogeocenoses), with regard to its long-term dynamics, in pine and spruce forests exposed to airborne industrial pollution from the Europe’s largest Severonikel Copper–Nickel Smelter Complex. Snowmelt waters from under the tree canopy, compared to those from intercrown areas, contain higher concentrations of chemical elements due to their washing and leaching from tree crowns. This is especially true of spruce forests, since the crowns of spruce trees have a high sorption capacity. Distinct trends in the long-term dynamics of snowmelt water composition, related to reduction of industrial emissions, are observed in background forest areas and defoliating forests but not in the vicinity of pollution sources. It is shown that the main factors determining these dynamics in forests of the Kola Peninsula are edificator tree species, airborne industrial pollution, and, possibly, an increase in the number of days with above-zero temperatures in the period of snow accumulation, which facilitates washing and leaching of chemical compounds from tree crowns. 相似文献
325.
326.
327.
328.
The aim of this research activity is to investigate the environmental impact of different thermal treatments of waste electric and electronic equipment (WEEE), applying a life cycle assessment methodology. Two scenarios were assessed, which both allow the recovery of bromine: (A) the co-combustion of WEEE and green waste in a municipal solid waste combustion plant, and (B) the staged-gasification of WEEE and combustion of produced syngas in gas turbines. Mass and energy balances on the two scenarios were set and the analysis of the life cycle inventory and the life cycle impact assessment were conducted. Two impact assessment methods (Ecoindicator 99 and Impact 2002+) were slightly modified and then used with both scenarios. The results showed that scenario B (staged-gasification) had a potentially smaller environmental impact than scenario A (co-combustion). In particular, the thermal treatment of staged-gasification was more energy efficient than co-combustion, and therefore scenario B performed better than scenario A, mainly in the impact categories of "fossil fuels" and "climate change". Moreover, the results showed that scenario B allows a higher recovery of bromine than scenario A; however, Br recovery leads to environmental benefits for both the scenarios. Finally the study demonstrates that WEEE thermal treatment for energy and matter recovery is an eco-efficient way to dispose of this kind of waste. 相似文献
329.
David Browne Bernadette ORegan Richard Moles 《Waste management (New York, N.Y.)》2009,29(10):2765-2771
This paper aims to measure product and waste flows in an Irish city-region using the principles of metabolism and mass balance. An empirical indicator to measure resource efficiency, using a ratio of waste disposal as a function of product consumption, was developed and it was found that total materials metabolic inefficiency fell by 31% from 0.13 in 1996 to 0.09 in 2002. The paper concludes by analyzing the strengths and weaknesses of this indicator and its potential application in the field of sustainable consumption and resource efficiency as well as making suggestions to improve and strengthen the indicator. 相似文献
330.
De-novo formation of dioxins and furans and the memory effect in waste incineration flue gases 总被引:1,自引:0,他引:1
The formation of dioxin (polychlorinated-rho-dibenzodioxins - PCDD) and furan (polychlorinated dibenzofurans - PCDF) in waste incineration flyash in relation to temperature has been investigated in a bench scale reactor. The PCDD/PCDF released into the exhaust gases of the reactor and trapped in a condensation and vapour phase adsorption system were also determined. The concentrations of PCDD/PCDF in the flyash were analysed in detail for all congeners and isomers including the mono-, di- and tri-PCDD/PCDF. De-novo synthesis of PCDD/PCDF was clearly seen in the flyash with large changes in concentrations of PCDD/PCDF with only small changes in temperature. Exhaust gas PCDD/PCDF were detected at all temperatures, with the maximum emission occurring at a flyash temperature of 350 degrees C, where the equivalent of over 42 times the total dioxin/furan concentration of the original flyash was lost to the vapour phase per unit mass of initial flyash. Although the desorbed species were mainly the lower mono- to tri-congener group of dioxins and furans, the desorbed dioxin/furans had a considerable toxic equivalent value. 相似文献