全文获取类型
收费全文 | 4154篇 |
免费 | 199篇 |
国内免费 | 1615篇 |
专业分类
安全科学 | 268篇 |
废物处理 | 288篇 |
环保管理 | 284篇 |
综合类 | 2418篇 |
基础理论 | 701篇 |
环境理论 | 1篇 |
污染及防治 | 1541篇 |
评价与监测 | 153篇 |
社会与环境 | 126篇 |
灾害及防治 | 188篇 |
出版年
2024年 | 1篇 |
2023年 | 68篇 |
2022年 | 194篇 |
2021年 | 163篇 |
2020年 | 135篇 |
2019年 | 117篇 |
2018年 | 139篇 |
2017年 | 190篇 |
2016年 | 185篇 |
2015年 | 243篇 |
2014年 | 286篇 |
2013年 | 439篇 |
2012年 | 359篇 |
2011年 | 359篇 |
2010年 | 282篇 |
2009年 | 287篇 |
2008年 | 312篇 |
2007年 | 268篇 |
2006年 | 235篇 |
2005年 | 188篇 |
2004年 | 121篇 |
2003年 | 145篇 |
2002年 | 158篇 |
2001年 | 99篇 |
2000年 | 122篇 |
1999年 | 143篇 |
1998年 | 116篇 |
1997年 | 107篇 |
1996年 | 104篇 |
1995年 | 113篇 |
1994年 | 77篇 |
1993年 | 66篇 |
1992年 | 49篇 |
1991年 | 32篇 |
1990年 | 14篇 |
1989年 | 6篇 |
1988年 | 15篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 9篇 |
1981年 | 3篇 |
排序方式: 共有5968条查询结果,搜索用时 15 毫秒
51.
本研究对兰州市不同污染区(石油化工为主、燃煤、商业及农村)在不同季节时的大气飘尘,作了对比采样.飘尘样品用溶剂抽提法提取后,用化学萃取法分离为五个有机物馏分.用毛细色谱-质谱-计算机联用系统进行了定性分析,并用毛细管色谱法进行了部分定量分析.用Ames试验(用TA1537、TA98和TA100三株菌.加与不加S-1)对其致突变活性进行了研究.并对有机致突变物在不同污染区、不同季节的变化规律及其来源进行了初步探讨. 相似文献
52.
53.
主成份分析法在大气环境质量综合评价中的应用 总被引:16,自引:1,他引:16
介绍了主成份分析法评价大气环境质量的基本原理,并对某市的大气环境质量进行了综合评价。最后,与其它方法的评价结果进行了对比分析,进一步证实了主成份分析法的科学性、合理性。 相似文献
54.
A Simulation of Temporal and Spatial Variations in Carbon at Landscape Level: A Case Study for Lake Abitibi Model Forest in Ontario,Canada 总被引:2,自引:0,他引:2
Xiaolu Zhou Changhui Peng Qing-Lai Dang Jiaxin Chen Sue Parton 《Mitigation and Adaptation Strategies for Global Change》2007,12(4):525-543
Using a case study of the Lake Abitibi Model Forest (LAMF), this study aims to assess the temporal and spatial variability
in carbon storage during 1990–2000, and to present a comprehensive estimation of the carbon budget for LAMF's ecosystems.
As well, it provided the information needed by local forest managers to develop ecological and carbon-based indicators and
monitor the sustainability of forest ecosystems. Temporal and spatial carbon dynamics were simulated at the landscape level
using ecosystem model TRIPLEX1.0 and Geographical Information System (GIS). The simulated net primary productivity (NPP) and
carbon storage in forest biomass and soil were compared with field data and results from other studies for Canada's boreal
forests. The results show that simulated NPP ranged from 3.26 to 3.34 tC ha−1 yr−1 in the 1990s and was consistent with the range measured during the Boreal Ecosystem-Atmosphere Studies (BOREAS) in central
Canada. Modeled NPP was also compared with the estimation from remote sensing data. The density of total above-and belowground
biomass was 125.3, 111.8, and 106.5 tC ha−1 for black spruce, trembling aspen, and jack pine in the LAMF ecosystem, respectively. The total carbon density of forested
land was estimated at 154.4 tC ha−1 with the proportion of 4:6 for total biomass and soil. The analysis of net carbon balance of ecosystem suggested that the
LAMF forest ecosystem was acting as a carbon sink with an allowable harvest in the 1990s. 相似文献
55.
在雾稳定的条件下,研究了雾滴穿过SO_2烟羽沉降到地面的过程中吸收、析解以及酸化等过程。结果表明,雾对烟羽中SO_2的清除具有某些奇特的现象。即仅在离源较远的区域才表现出有限的清除作用:而在近源区,主要以析解为主,使源附近地面SO_2浓度增加,高架源成了低架源。雾滴在地面附近的这种析解作用,是造成雾天污染物浓度高的重要原因之一。 相似文献
56.
57.
58.
Liu Rui Zhou Qixing Zhang Lanying Guo Hao 《Frontiers of Environmental Science & Engineering in China》2007,1(1):114-119
To make a comprehensive assessment on monosodium glutamate (MSG) wastewater pollution, a pollution exposure experiment was
carried out on the seed germination and root elongation of wheat, Chinese cabbage and tomato by using the wastewater discharged
from different processing phases of MSG production. The results showed that there were significantly positive linear relationships
between the inhibitory rates of wheat seed germination and root elongation and the CODcr of the mother liquor scraps. The toxicity of MSG wastewater to the test crops was in the order of tomato > Chinese cabbage
> wheat, indicating that tomato was the most sensitive to the wastewater, and could be considered as an ideal toxic bioindicator.
The half-effect concentrations (IC50) based on the seed germination and root elongation of the test crops exposed to the wastewater discharged from various processing
phases of MSG production was 22.0–32 432 and 17.3–3320 mg/L, respectively.
Translated from Chinese Journal of Applied Ecology, 2006, 17(7): 1286–1290 [译自: 应用生态学报] 相似文献
59.
分析了影响截流倍数的影响因素,探讨了合理的截流倍数计算方法。通过某城市实例分析.发现合流制截流倍数应综合考虑合流水量.截流规模.排放污染物总量、水体排放要求及水体自净能力等,最终通过计算比较后确定。 相似文献
60.