全文获取类型
收费全文 | 6816篇 |
免费 | 427篇 |
国内免费 | 1016篇 |
专业分类
安全科学 | 299篇 |
废物处理 | 71篇 |
环保管理 | 1895篇 |
综合类 | 3281篇 |
基础理论 | 647篇 |
污染及防治 | 494篇 |
评价与监测 | 1283篇 |
社会与环境 | 246篇 |
灾害及防治 | 43篇 |
出版年
2024年 | 40篇 |
2023年 | 126篇 |
2022年 | 158篇 |
2021年 | 182篇 |
2020年 | 200篇 |
2019年 | 151篇 |
2018年 | 140篇 |
2017年 | 220篇 |
2016年 | 265篇 |
2015年 | 286篇 |
2014年 | 332篇 |
2013年 | 424篇 |
2012年 | 428篇 |
2011年 | 495篇 |
2010年 | 333篇 |
2009年 | 374篇 |
2008年 | 334篇 |
2007年 | 455篇 |
2006年 | 410篇 |
2005年 | 313篇 |
2004年 | 276篇 |
2003年 | 285篇 |
2002年 | 266篇 |
2001年 | 214篇 |
2000年 | 212篇 |
1999年 | 162篇 |
1998年 | 133篇 |
1997年 | 125篇 |
1996年 | 126篇 |
1995年 | 94篇 |
1994年 | 89篇 |
1993年 | 60篇 |
1992年 | 49篇 |
1991年 | 57篇 |
1990年 | 26篇 |
1989年 | 32篇 |
1988年 | 40篇 |
1987年 | 31篇 |
1986年 | 24篇 |
1985年 | 19篇 |
1984年 | 22篇 |
1983年 | 23篇 |
1982年 | 27篇 |
1981年 | 27篇 |
1980年 | 31篇 |
1979年 | 28篇 |
1978年 | 18篇 |
1977年 | 15篇 |
1975年 | 15篇 |
1973年 | 18篇 |
排序方式: 共有8259条查询结果,搜索用时 718 毫秒
581.
水环境质量综合评价的新模型 总被引:23,自引:0,他引:23
为检验已订的水环境质量评价标准的合理性,解决各单项水质指标的评估结果的不相容性问题,提高水质等级模型的分辨率,提出了一种新的水质评价模型-逻辑斯谛曲线(LOG)模型,它的水质等级是连续的实数值;根据LOG模型的参数值可以分析各水质指标值对水质等级的影响程度,从而检验原订水质等级标准的合理性;并给出了基于实码遗传算法的LOG建模的实施方案.实例研究说明,这套方案是实用的和通用的,在其它环境质量综合评价中也具有广泛的应用价值. 相似文献
582.
用蚕豆根尖细胞微核技术检测乌鲁木齐河水质 总被引:2,自引:0,他引:2
应用蚕豆根尖细胞微核技术对乌鲁木齐水质进行检测,测定各样点水样诱导的蚕豆根尖微核千分率及综合污染指数,并进行F检验,结果表明,各样点MCN‰有显著性差异,20个样点中有11个样点 的综合污染指数大于2,4个样点水样的综合污染指数大于3.5,和对照组相比有显著差异。所获得数据表明乌鲁木齐河水质受到较为了严重的致突变性污染。 相似文献
583.
简要介绍了纸片法测定水质总大肠菌群的操作方法,并通过6个实验室的验证试验,研究了纸片法与现行标准方法(多管法)的一致性。结果表明,2种方法的测定结果基本一致,无显著性差异,但纸片法测定周期比多管法缩短了2d,仅需1d即可。 相似文献
584.
585.
586.
伊犁河伊宁市段水质污染特征分析 总被引:3,自引:1,他引:2
在对伊犁河伊宁市段历年水质状况进行综合评价的基础上,探讨了城市河段水质的变化规律、污染特征和成因。 相似文献
587.
The long-term water quality monitoring program implemented by the Massachusetts Water Resources Authority in 1992 is extensive
and has provide substantial understanding of the seasonality of the waters in both Boston Harbor and Massachusetts Bay and
the response to improvements in effluent quality and offshore transfer of the effluent in September 2000. The monitoring program
was designed with limited knowledge of spatial and temporal variability and long-term trends within the system. This led to
an extensive spatial and temporal sampling program. The data through 2003 showed high correlation within physical parameters
measured (e.g., salinity, dissolved oxygen) and in biological measures such as chlorophyll fluorescence. To address the potential
sampling redundancies in the measurement program, an assessment of the impact of reduced levels of monitoring on the ability
to make water quality decisions was completed. The optimization was conducted by applying statistical models that took into
account whether there was evidence of a seasonal pattern in the data. The optimization used model survey average readings
to identify temporal fixed effects, model survey-average-corrected individual station readings to identify spatial fixed effects,
corrected the individual station readings for temporal and spatial fixed effects and derived a correlation model for the corrected
data, and applied the correlation model to characterize the correlation of annual average readings from reduced monitoring
programs with true parameter levels. Reductions in the number of sampling stations were found less detrimental to the quality
of the data for annual decision-making than reductions in the number of surveys per year, although there is less of a difference
in this regard for dissolved oxygen than there is for chlorophyll. The analysis led to recommendations for a substantially
lower monitoring effort with minimal loss of information. The recommendation supported an annual budget savings of approximately
$183,000. Most of the savings was from fewer surveys as approximately $21,000 came from the reduction in the number of stations
monitored from 21 to 7 and associated laboratory analytical costs. 相似文献
588.
Klopchin JL Stewart JR Webster LF Sandifer PA 《Environmental monitoring and assessment》2008,137(1-3):301-313
Morgan Island, located within the ACE Basin National Estuarine Research Reserve in South Carolina, is home to the only free-ranging
colony of rhesus monkeys (Macca mulatta) in the continental United States. The purpose of this study was to assess environmental impacts of the monkey colony on
water quality in adjacent tidal creeks and on island vegetation. Three tidal creeks were sampled: Morgan Creek, adjacent to
the monkey colony; Back Creek, on Morgan Island not adjacent to the colony; and Rock Creek, on a nearby island unoccupied
by monkeys. Temperature, salinity, pH, dissolved oxygen, nutrients and fecal coliform bacteria were measured six times at
three sites in each of these creeks, and vegetation change analysis was conducted in a geographic information system using
satellite imagery. Results showed elevated fecal coliform concentrations in the Morgan Creek site immediately adjacent to
the colony, though no samples exceeded the standard set for recreational water use. Ribotyping reconnaissance matched four
Escherichia coli isolates from Morgan and Back Creeks to the monkeys, identifying the colony as one source of fecal coliform bacteria, though
relative source loadings could not be quantified. Significant differences were not observed between ammonia or orthophosphate
levels in Morgan Creek relative to the other creeks tested; and vegetation change analysis showed a 35% increase in canopy
cover between 1979 and 1999. Overall, these results suggest that the rhesus colony’s environmental impacts are localized and
minimal. Results from this study provide baseline data on Morgan Island and may be useful in management decisions regarding
the future of the monkey colony. 相似文献
589.
Heavy metal contamination from mining sites in South Morocco: Monitoring metal content and toxicity of soil runoff and groundwater 总被引:5,自引:0,他引:5
El Khalil H El Hamiani O Bitton G Ouazzani N Boularbah A 《Environmental monitoring and assessment》2008,136(1-3):147-160
The aim of the present work is the assessment of metal toxicity in runoff, in their contaminated soils and in the groundwater
sampled from two mining areas in the region of Marrakech using a microbial bioassay MetPLATE™. This bioassay is based on the
specific inhibition of the β-galactosidase enzyme of a mutant strain of Escherichia coli, by the metallic pollutants. The stream waters from all sampling stations in the two mines were all very toxic and displayed
percent enzyme inhibition exceeding 87% except SWA4 and SWB1 stations in mine C. Their high concentrations of copper (Cu) and zinc (Zn) confirm the acute toxicity shown by MetPLATE.
The pH of stream waters from mine B and C varied between 2.1 and 6.2 and was probably responsible for metal mobilization,
suggesting a problem of acid mine drainage in these mining areas. The bioassay MetPLATE™ was also applied to mine tailings
and to soils contaminated by the acidic waters. The results show that the high toxicity of these soils and tailings was mainly
due to the relatively concentration of soluble Zn and Cu. The use of MetPLATE™ in groundwater toxicity testing shows that,
most of the samples exhibited low metal toxicity (2.7–45.5% inhibition) except GW3 of the mine B (95.3% inhibition during
the wet season and 82.9% inhibition during the dry season). This high toxicity is attributed to the higher than usual concentrations
of Cu (189 μg Cu l−1) and Zn (1505 μg Zn l−1). These results show the potential risk of the contamination of different ecosystems situated to the vicinity of these two
metalliferous sites. The general trend observed was an increase in metal toxicity measured by the MetPLATE with increasing
total and mobile metal concentrations in the studied matrices. Therefore, the MetPLATE bioassay is a reliable and fast bioassay
to estimate the metals toxicity in the aquatic and solids samples. 相似文献
590.
Majagi SH Vijaykumar K Vasanthkaumar B 《Environmental monitoring and assessment》2008,138(1-3):273-279
In this study, some heavy metals concentrations (Zn, Pb, Fe, Mn, Cu, Ni) and other physico-chemical parameters were studied
during October 2001 to September 2003 in Karanja reservoir, Bidar district. Water quality parameters were collected monthly
basis whereas heavy metals were analyzed by Atomic Adsorption Spectrometer (AAS). Heavy metals have shown within the permissible
limits, except Fe and Ni were recorded higher values in southwest monsoon, where as Mn has showed higher concentration in
northeast monsoon in and summer. All other physico-chemical parameters are with in the permissible limit. Water is moderately
hard and reservoir is productive. 相似文献