全文获取类型
收费全文 | 1158篇 |
免费 | 197篇 |
国内免费 | 402篇 |
专业分类
安全科学 | 169篇 |
废物处理 | 30篇 |
环保管理 | 86篇 |
综合类 | 937篇 |
基础理论 | 166篇 |
污染及防治 | 108篇 |
评价与监测 | 96篇 |
社会与环境 | 109篇 |
灾害及防治 | 56篇 |
出版年
2024年 | 7篇 |
2023年 | 26篇 |
2022年 | 95篇 |
2021年 | 92篇 |
2020年 | 103篇 |
2019年 | 60篇 |
2018年 | 73篇 |
2017年 | 87篇 |
2016年 | 68篇 |
2015年 | 74篇 |
2014年 | 45篇 |
2013年 | 105篇 |
2012年 | 108篇 |
2011年 | 110篇 |
2010年 | 90篇 |
2009年 | 83篇 |
2008年 | 86篇 |
2007年 | 88篇 |
2006年 | 89篇 |
2005年 | 75篇 |
2004年 | 40篇 |
2003年 | 31篇 |
2002年 | 25篇 |
2001年 | 27篇 |
2000年 | 28篇 |
1999年 | 13篇 |
1998年 | 1篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有1757条查询结果,搜索用时 15 毫秒
881.
882.
水质监测中存在的若干技术问题 总被引:10,自引:0,他引:10
在全国持证上岗、计量认证、实验室现场考核和《亚洲地区实验室精度管理手册》编制过程及监测质量调查的基础上,发现我国部分环境监测站在水质监测的实际操作、试样前处理、监测分析方法选择及数据分析等方面尚存在一些技术问题。在分析这些问题的同时,提出了解决办法和完善我国质量保证指标体系的建议。 相似文献
883.
Assessment of Wastewater Reuse Effects on Nutrient Loads from Paddy Field Using Field-Scale Water Quality Model 总被引:1,自引:0,他引:1
Sang Min Kim Sang June Im Seung Woo Park Jeong Jae Lee Brian L. Benham Tae Il Jang 《Environmental Modeling and Assessment》2008,13(2):305-313
CREAMS-PADDY, a modified version of the field-scale CREAMS model, simulates the hydrologic, sediment, and nutrient cycles
in paddy fields. The CREAMS-PADDY model was applied to estimate the effects of using wastewater for irrigation on nutrient
loads from paddy fields in Republic of Korea. The model was calibrated and validated using data from two rice paddy fields.
The coefficient of determination between observed and simulated total nitrogen and total phosphorus were 0.92 and 0.57, respectively,
for the calibration period and 0.84 and 0.73 for the validation period. Simulations showed that when using wastewater for
irrigation, the total nitrogen loads increased by 210% and total phosphorus by 1,270% when compared with conventional water
irrigation. The total nitrogen and total phosphorus concentration in the ponded water increased by 254 and 534%, respectively,
when compared with conventional water irrigation. The effect of reducing N and P fertilizer application rates by 10, 30, and
50% on nutrient loads exiting a paddy field were also simulated using the validated CREAMS-PADDY model. These simulations
indicated that total phosphorus loads from the paddy were reduced only slightly by reducing the fertilizer, while total nitrogen
loads were reduced by as much as 8.8, 16.6, and 24.4% when N ferlitizer rates were reduced by 10, 30, and 50%, respectively.
An erratum to this article can be found at 相似文献
884.
885.
886.
These days, wildfires are prevalent in almost all areas of the world. Researchers have been actively analyzing wildfire damage using a variety of satellite images and geospatial datasets. This paper presents a method for detailed estimation of wildfire losses using various geospatial datasets and an actual case of wildfire at Kang-Won-Do, Republic of Korea in 2005. A set of infrared (IR) aerial images acquired after the wildfire were used to visually delineate the damaged regions, and information on forest type, diameter class, age class, and canopy density within the damaged regions was retrieved from GIS layers of the Korean national forest inventory. Approximate tree heights were computed from airborne LIDAR and verified by ground LIDAR datasets. The corresponding stand volumes were computed using tree volume equations (TVE). The proposed algorithm can efficiently estimate fire loss using the geospatial information; in the present case, the total fire loss was estimated as $5.9 million, which is a more accurate estimate than $4.5 million based on conventional approach. The proposed method can be claimed as a powerful alternative for estimating damage caused by wildfires, because the aerial image interpretation can delineate and analyze damaged regions in a comprehensive and consistent manner; moreover, LIDAR datasets and national forest inventory data can significantly reduce field work. 相似文献
887.
888.
An enhanced dual coil 2,4-dinitrophenylhydrazine (DNPH) derivatization method (dual coil/DNPH) allowed the quantitative determination
of formaldehyde (HCHO) in ambient air. In this method, traceable HCHO was collected using a coil sampler connected in series
and lacking a long sampling tube. It was then analyzed using liquid chromatography followed by UV detection of the DNPH derivatives.
The method is based on the reaction of formaldehyde with DNPH to produce 2,4-dinitrophenylhydrazone. The detection limits
(3σ) were 0.10–0.40 ppbv with a precision ranging from 0.84 to 4.09% RSD. The results of dual coil/DNPH and conventional DNPH
cartridge methods were generally well correlated: HCHO (dual coil/DNPH) = 0.97 (±0.13) vs. HCHO (DNPH Cartridge) + 0.33 (±0.33),
r = 0.82. The dual coil/DNPH method was used to measure gaseous HCHO in the atmosphere of Metropolitan Seoul during the summer
2000 and 2001, and in Gwangju during the fall of 2001 and 2002. The daytime mean concentration of HCHO was 4.52 (±5.69) and
3.21 (±1.27) ppbv in Metropolitan Seoul for 10–12 August 2000 and 29–31 May 2001, respectively, and 1.73 (±0.98), 3.04 (±2.25),
2.70 (±1.70), and 2.01 (±2.28) ppbv in Gwangju City during 22–27 September 2001, 17–24 October 2001, 9–13 October 2002, and
28 October to 2 November 2002, respectively. The HCHO in Seoul from 10–12 August 2000 was mainly the result of photochemical
processes, while direct emissions from vehicles and long-range transport of air from China contributed during 29–31 May 2001.
During 22–27 September 2001, 17–24 October 2001, and 9–13 October 2002 in Gwangju, the HCHO came primarily from photochemical
processes, although some air affected by biomass burning admixed in the late afternoon. The increase in the HCHO concentration
on 20 October 2001 and from 28 October to 2 November 2002 was attributed mainly to direct emissions from biomass burning in
farmland near the measurement site. 相似文献
889.
中国生态监测存在问题及发展趋势 总被引:1,自引:1,他引:0
在生态学的基本理论基础上,探讨了生态监测的科学内涵,明确了生态监测对象就是生态系统,目标是认识反映生态系统的状态和演变趋势,为管理和决策提供科学依据。深入分析了中国生态监测存在的5个问题:生态监测缺乏统一管理,部门间任务存在交叉和重复;生态监测技术不够规范,信息整合与利用困难;生态监测网络松散,国家级生态监测网络建立缓慢;环境监测法律依据不足,法制保障力度亟待加强;生态监测能力水平普遍较低,亟待建设。最后,从国家现实需求、生态监测现状以及监测技术发展的历史规律,探讨了未来中国生态监测的总体发展趋势。 相似文献
890.