全文获取类型
收费全文 | 1392篇 |
免费 | 86篇 |
国内免费 | 546篇 |
专业分类
安全科学 | 71篇 |
废物处理 | 94篇 |
环保管理 | 106篇 |
综合类 | 738篇 |
基础理论 | 285篇 |
污染及防治 | 556篇 |
评价与监测 | 86篇 |
社会与环境 | 47篇 |
灾害及防治 | 41篇 |
出版年
2024年 | 4篇 |
2023年 | 13篇 |
2022年 | 62篇 |
2021年 | 47篇 |
2020年 | 42篇 |
2019年 | 59篇 |
2018年 | 52篇 |
2017年 | 71篇 |
2016年 | 77篇 |
2015年 | 129篇 |
2014年 | 117篇 |
2013年 | 150篇 |
2012年 | 122篇 |
2011年 | 122篇 |
2010年 | 94篇 |
2009年 | 93篇 |
2008年 | 123篇 |
2007年 | 99篇 |
2006年 | 74篇 |
2005年 | 57篇 |
2004年 | 55篇 |
2003年 | 48篇 |
2002年 | 42篇 |
2001年 | 37篇 |
2000年 | 29篇 |
1999年 | 34篇 |
1998年 | 29篇 |
1997年 | 26篇 |
1996年 | 24篇 |
1995年 | 19篇 |
1994年 | 15篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1977年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有2024条查询结果,搜索用时 31 毫秒
921.
922.
Water resource management traditionally depends on use of highly complex hydrological models designed originally to manage
water for abstraction but increasingly relied on to determine ecological impacts and test ecological rehabilitation opportunities.
These models are rarely independently tested. We compared a relatively simple statistical model, integrated flow and flood
modelling (IFFM), with a complex hydrological model, the integrated quality and quantity model (IQQM), on the highly regulated
Macquarie River of the Murray-Darling Basin, southeastern Australia. We compared annual flows (1891–2007) at three gauges
to actual data and modelled output: before dams and diversions (unregulated) and after river regulation (regulated), using
the goodness of fit (Nash-Sutcliffe coefficient of efficiency) and nonparametric tests. IQQM underestimated impacts of river
regulation respectively on median and average flows at the Macquarie Marshes (Oxley gauge) by about 10% and 16%, compared
to IFFM. IFFM model output more closely matched actual unregulated and regulated flows than IQQM which tended to underestimate
unregulated flows and overestimate regulated flows at the Ramsar-listed wetland. Output was reasonably similar for the two
models at the other two flow gauges. Relatively simple statistical models could more reliably estimate ecological impact at
floodplains of large river systems, as well as an independent assessment tool compared to complex hydrological models. Finally,
such statistical models may be valuable for predicting ecological responses to environmental flows, given their simplicity
and relative ease to run. 相似文献
923.
Narran Lakes is a Ramsar site recognised for its importance for colonial waterbird breeding, which only occurs after large
highly variable flooding events. In 2008, 74,095 pairs of ibis bred for the first time in seven years, establishing two contiguous
colonies, a month apart. Most (97%) of the colony consisted of the straw-necked ibis (Threskiornis spinicollis) with the remainder consisting of glossy ibis (2%, Plegadis falcinellus) and Australian white ibis (1%, T. molucca). Following cessation of river flows, water levels fell rapidly in the colony site, resulting in a crisis management decision
by governments to purchase and deliver water (10,423 Ml) to avert mass desertion of the colonies. There were significant differences
in the reproductive success of each colony. In colony 1 60% of eggs hatched and 94% of chicks fledged, while in colony 2 40%
of eggs hatched with only 17% of chicks fledging. Statistical analyses found that water depth was a significant variable in
determining reproductive success. Rapid falls in water level during the chick stage in colony 2 resulted in decreased chick
and overall offspring success. The results of this study identify the impact of upstream water resource development on colonial
waterbird breeding and have implications for water management policies. 相似文献
924.
采煤沉陷已成为煤矿区危害范围最广、影响程度最大、延续时间最长的一种工程地质灾害,在对赵各庄煤矿矿山地质环境调查的基础上,分析采空沉陷区对土地资源影响特征,并预测采空沉陷区土地资源影响和破坏发展趋势,指出了沉陷区土地复垦规划原则,提出了合理的复垦建议。 相似文献
925.
内蒙古地区近25年植被对气温和降水变化的影响 总被引:5,自引:0,他引:5
利用1982—2006年内蒙古地区GIMMS-NDVI和降水量、气温数据,分析了不同植被类型对气温和降水变化趋势的影响。结果表明:近25年来内蒙古地区气温整体上呈上升趋势,降水量呈微弱降低趋势,西部荒漠区呈暖湿化趋势,中东部草原、森林等植被类型区呈暖干化趋势;从不同植被类型NDVI与平均气温和降水量的变化趋势率相关分析表明,NDVI值越低,升温趋势越明显,其中春季和秋季各植被类型间NDVI与季均气温升高趋势率呈显著和较显著的相关,夏、冬季关系不明显;植被NDVI越高,降水量减少趋势越明显。基于栅格的NDVI与气温升高幅度、降水变化趋势相关分析表明,年均气温升高幅度基本随NDVI的增加而降低,其中春、夏和秋季的季均气温升高幅度均随NDVI的增加而显著降低,冬季趋势不明显;而年降水量减小趋势率随植被NDVI的增加而显著增加,其中春季和冬季NDVI变化对降水的变化几乎没有影响;夏季和秋季均表现为随NDVI的增加,降水减小趋势率呈增加趋势。 相似文献
926.
In the process of mining activity, many kinds of heavy metals enter into soils with dust, causing serious contamination to the environment. In this study, six soils were sampled from cropland at different distances from a lead/zinc mine in Heilongjiang Province, China. The total contents of lead and zinc in the vicinal cropland exceeded the third level of environmental quality standard for soil in China, which indicated that soils in this area were moderately contaminated. Bacterial community diversity and population were greatly decreased when the concentrations of lead and zinc were beyond 1,500 and 995 mg kg(-1), respectively, as analyzed by plate counting and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The bands of DGGE patterns varied with the degree of contamination. The activities of soil urease, phosphatase, and dehydrogenase were negatively correlated with the concentrations of lead and zinc. The highest inhibitory effect of heavy metals on soil enzyme activities was observed in urease. It was noted that PCR-DGGE patterns combined with soil enzyme activity analysis can be indices for the soil quality assessment by heavy metal contamination. 相似文献
927.
Zhang W Wei C Feng C Yu Z Ren M Yan B Peng P Fu J 《Journal of environmental monitoring : JEM》2011,13(12):3429-3436
Nineteen soil samples were collected in and around Songshan coking plant in Guangdong province of China and analyzed for eighteen polycyclic aromatic hydrocarbons (PAHs) by gas chromatography-mass spectrometry (GC-MS). The total concentration of PAHs ranged from 2.36 to 1146.39 mg kg(-1) dry weight, varying significantly among the sampling sites, most individual PAHs were correlated with each other. A cluster analysis was performed to examine the correlation of PAH distribution, five groups were observed with sample types in the coking plant. 2-3 ring PAHs were predominant in group I and II, while 4-5 ring PAHs showed great abundance in group III, IV and V, which contributed to the distance from the emission sources in the coking plant and the behaviors of particle-bound and gaseous PAHs. The ratios of Flu?:?(Flu + Pyr), BaA?:?(BaA + Chr), InP?:?(InP + BgP) and Ant?:?(Ant + Phen) ratios were 0.51-0.87, 0.16-0.89, 0.47-0.68 and 0.03-0.60, respectively. The total index of all studied soils was > 6, indicating that the source of the PAHs in coking plant soils were from the pyrolysis processes. Health risk assessments were carried out by dermal PAH exposure data to quantify cancer risk. The resultant lifetime exposure levels due to TEQ(BaP) desorbed onto skin for workers ranged from 2.25 × 10(-7) to 7.86 × 10(-5) mg kg(-1) per day, and the estimated cancer risks were between 8.45 × 10(-6) and 2.94 × 10(-3), indicating that the dermal exposures of PAHs to coking workers might be acceptable in most soil sites. 相似文献
928.
Chen Zailin Huang Yi Cheng Xin Ni Shijun Wang Jinjin Ren Bangzheng Yu Qiulian 《Environmental science and pollution research international》2021,28(2):1850-1865
Environmental Science and Pollution Research - We attempt to understand the pollution characteristics and carcinogenic risk of toxic elements around Hutou Village, Xuanwei City, Yunnan Province,... 相似文献
929.
Zhang Xiaoqing Ren Jianlan 《中国人口.资源与环境(英文版)》2007,5(3):37-42
This paper aims at studying the dynamic mechanism of urban expansion and its role. Based on the economic model of urban spatial structure and applying panel data in Shandong Province, the paper concludes. Economic growth and transition of economic structure have played the most powerful role in urban expansion. An increase in population helps the core to extend. Increasing agricultural productivity can provide a countervailing force. An increase in transportation costs will limit urban expansion. An increase in the marginal productivity of land in housing production will increase urban expansion. Fiscal and taxation policies also have encouraged the extensive shift of cultivated land into build-up area. This paper also suggests that if high rate increasing GDP is needed, the urban core will continue to expand. The government should take measures to improve the rapid growth of the city. 相似文献
930.
影响津河水生生态环境的主要因素及保护对策 总被引:3,自引:0,他引:3
论述了津河改造后整体水生生态环境的改善成效,对影响津河生态环境的城市径流、工业废水、生活垃圾、海河水质、津河底质等因素进行分析,并提出了相关的防护措施和建议。 相似文献