全文获取类型
收费全文 | 13721篇 |
免费 | 1834篇 |
国内免费 | 8018篇 |
专业分类
安全科学 | 2229篇 |
废物处理 | 528篇 |
环保管理 | 1226篇 |
综合类 | 12994篇 |
基础理论 | 2738篇 |
环境理论 | 3篇 |
污染及防治 | 2395篇 |
评价与监测 | 756篇 |
社会与环境 | 455篇 |
灾害及防治 | 249篇 |
出版年
2024年 | 63篇 |
2023年 | 487篇 |
2022年 | 735篇 |
2021年 | 874篇 |
2020年 | 832篇 |
2019年 | 886篇 |
2018年 | 769篇 |
2017年 | 741篇 |
2016年 | 864篇 |
2015年 | 983篇 |
2014年 | 941篇 |
2013年 | 1446篇 |
2012年 | 1517篇 |
2011年 | 1587篇 |
2010年 | 1111篇 |
2009年 | 1322篇 |
2008年 | 1008篇 |
2007年 | 1180篇 |
2006年 | 1184篇 |
2005年 | 837篇 |
2004年 | 701篇 |
2003年 | 613篇 |
2002年 | 499篇 |
2001年 | 424篇 |
2000年 | 368篇 |
1999年 | 310篇 |
1998年 | 221篇 |
1997年 | 203篇 |
1996年 | 164篇 |
1995年 | 151篇 |
1994年 | 109篇 |
1993年 | 101篇 |
1992年 | 76篇 |
1991年 | 43篇 |
1990年 | 35篇 |
1989年 | 25篇 |
1988年 | 18篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1982年 | 15篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1971年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
运用灰色系统理论,结合实例详细介绍了GM(1,1)模型在大气环境浓度预测中的应用。 相似文献
92.
对GAM水环境预测模型提出了四点不同看法,与有关作者商榷,指出GM(1,1)模型与GAM模型二者并无优劣之差,精度亦相当。 相似文献
93.
唐山市空气中SO2与TSP污染状况分析 总被引:1,自引:0,他引:1
分析了唐山市从1988年至1992年大气中SO2和TSP的污染状况和变化规律,取得对该市环境管理的科学依据。 相似文献
94.
Alexander Baklanov 《Environmental monitoring and assessment》2000,65(1-2):181-189
Different urban air pollution problems deal with complex structure of air flows and turbulence. For such problems the Computer Fluid Dynamics (CFD) methods become widely used. However, this approach despite a number of advantages has some problems. Experience of use of CFD tools for development of models and suggestions of their applications for a local scale air pollution over a complex terrain and stable stratification are discussed in this paper, including: Topography and complex geometry: choose of the co-ordinate system and computer grid; Turbulence closure for air pollution modelling: modified k- model for stable stratified ABL; Boundary conditions for vertical profiles of velocity for stable-stratified atmosphere; Effects of the radiation and thermal budget of inclined surfaces to dispersion of pollutants; Artificial sources of air dynamics and circulation.Some examples of CFD applications for air pollution modelling for a flat terrain, mountainous area, mining open cast and indoor ventilation are discussed. Modified k- model for stably-stratified ABL is suggested. Due to the isotropic character of the k- model a combination of it in vertical with the sub-grid turbulence closure in horizontal can be more suitable for ABL. An effective scheme of boundary conditions for velocity profiles, based on the developed similarity theory for stable-stratified ABL, is suggested. Alongside with the common studies of atmospheric dispersion, the CFD methods have also demonstrated a good potential for studying anthropogenic and artificial-ventilation sources of air dynamic and circulation in local-scale processes of air pollution. 相似文献
95.
Geostatistical Uncertainty Modelling for the Environmental Hazard Assessment During Single Erosive Rainstorm Events 总被引:1,自引:0,他引:1
Diodato N 《Environmental monitoring and assessment》2005,105(1-3):25-42
This paper presents an environmental hazard assessment to account the impacts of single rainstorm variability on river-torrential landscape identified as potentially vulnerable mainly to erosional soil degradation processes. An algorithm for the characterisation of this impact, called Erosive Hazard Index (EHI), is developed with a less expensive methodology. In EHI modelling, we assume that the river-torrential system has adapted to the natural hydrological regime, and a sudden fluctuation in this regime, especially those exceeding thresholds for an acceptable range of flexibility, may have disastrous consequences for the mountain environment. The hazard analysis links key rainstorm energy variables expressed as a single-storm erosion index (EIsto), with impact thresholds identified using an intensity pattern model. Afterwards, the conditional probabilities of exceeding these thresholds are spatially assessed using non-parametric geostatistical techinques, known as indicator kriging. The approach was applied to a test site in river-torrential landscape of the Southern Italy (Benevento province) for 13 November 1997 rainstorm event. 相似文献
96.
J. Franzaring 《Environmental monitoring and assessment》1997,46(3):209-220
Up to now only very few studies in biomonitoring of organic air pollutants have been published taking into account the strong influence mean temperatures have on the accumulation process into plants during the course of the exposition. Temperature governed sorption as well as the plants vitality pose a major source of uncertainty making inter-study comparisons difficult. Different surface-to-volume ratios of plant foliage lead to strongly varying concentration effects in different plant species. Moreover a plants content of waxes and lipids must be considered in order to relate xenobiotic concentrations to the compounds being most efficient in the bioaccumulation process. Some of these factors are evaluated in regard to the use of plants as biomonitors for organic air pollutants. Another aim is to deduce the mean ambient gas phase concentrations from PAH concentrations determined in the biomonitor plants using vegetation-air partitioning coefficients which have been corrected for temperature dependent sorption as well as the plants lipid content. Restrictions of such approaches and methods of biomonitoring in general are discussed. 相似文献
97.
98.
1985年~1989年由新疆、甘肃、青海、西藏、内蒙古、陕西、宁夏等省、自治区环境监测站(研究所)对内陆流域各类水体中U、Th、~(226)Ra、~(40)K浓度进行调查,由调查的29条内陆河、23个湖泊、15座水库、55处井泉和34个自来水的统计结果表明,流域内各水体中U和~(40)K浓度的平均值与同期调查的黄河水系同类水体的浓度相近,明显高于长江水系,与全国同类水体相比亦属偏高。Th和~(226)Ra的平均浓度与全国同类水体的浓度相近,甘、新内陆区浓度较低。调查发现,一些咸水湖、井水和自来水中U、~(226)Ra,或~(40)K浓度异常偏高。 相似文献
99.
Fractionation of Cu, Pb and Zn in certified reference soils SRM 2710 and SRM 2711 using the optimized BCR sequential extraction procedure 总被引:4,自引:0,他引:4
Sequential extraction of metals from solid media is a common analytical tool used in environmental and exploration geochemistry. A number of procedures exist, but without harmonization and standardization, meaningful comparisons are tenuous without baseline data. A newly developed, standardized sequential extraction procedure (optimized BCR) was applied to two contaminated certified reference soils from Montana, US (SRM 2710 and SRM 2711) for Cu, Pb and Zn. Four operationally defined fractions were isolated, acid extractable, reducible, oxidizable, and residual (by aqua regia). Fraction-specific concentrations, percentages and recoveries for Cu, Pb and Zn were used to explore differences between the optimized BCR procedure and three other sequential extraction schemes with published data for SRM 2710 and 2711 (i.e. Tessier scheme, Geological Survey of Canada scheme and the original BCR scheme). Results indicate significant differences between the four schemes, even for schemes that are closely associated (i.e. the original and optimized BCR schemes). Order-of-magnitude fraction-specific concentration differences were observed, especially for Pb in the reducible fraction. Differences between schemes are worrisome because trends varied between metals, between fractions and between reference soils. These data reinforce the need for increased adoption of standardized sequential extraction procedures and further examination of different solid media. 相似文献
100.