全文获取类型
收费全文 | 338篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 15篇 |
环保管理 | 35篇 |
综合类 | 58篇 |
基础理论 | 73篇 |
污染及防治 | 126篇 |
评价与监测 | 24篇 |
社会与环境 | 7篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 21篇 |
2012年 | 14篇 |
2011年 | 24篇 |
2010年 | 9篇 |
2009年 | 7篇 |
2008年 | 23篇 |
2007年 | 22篇 |
2006年 | 15篇 |
2005年 | 19篇 |
2004年 | 10篇 |
2003年 | 12篇 |
2002年 | 16篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 8篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1978年 | 2篇 |
1973年 | 1篇 |
1965年 | 1篇 |
1960年 | 3篇 |
1959年 | 2篇 |
1958年 | 2篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1955年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有343条查询结果,搜索用时 15 毫秒
161.
162.
163.
164.
165.
一种基于MMS的改进降水径流模型在中国西北地区黑河上游流域的应用 总被引:7,自引:1,他引:6
以黑河流域上游为研究对象,通过对山区自然产水区的产汇流机理的研究,基于分布式水文模型集成环境的开发思想,利用MMS(modular modeling system)模型库中与降水径流相关的模块,通过综合各种产流(包括超渗、蓄满产流)机理、并且根据寒区产汇流的特点对USGS开发的流域PRMS(precipitation-runoff models)模型进行了改进,增加了土壤水运动中降雨入渗补给的多层土壤滞后效应模块以及积雪融雪和冻土面积识别模型,建立了适合于寒区流域的分布式PRMS模型。利用该模型对黑河上游出山径流过程进行了模拟与预报,模型研究结果表明:利用MMS建立的黑河上游改进的PRMS模型不仅完全可以模拟和预测黑河上游的产汇流过程,在考虑了冻土的情况下,预测年出山径流量误差小于2.7%;而且模型可以对黑河上游径流组成成分进行分析计算,对黑河上游产汇流机理做进一步阐明。利用改进的PRMS模型,预测分析了黑河上游未来气候和土地覆盖变化情景下流域出山径流变化的趋势,为黑河流域水资源合理利用和管理提供科学依据。 相似文献
166.
Duester L Diaz-Bone RA Kösters J Hirner AV 《Journal of environmental monitoring : JEM》2005,7(12):1186-1193
Methylated species of antimony, arsenic and tin were examined in urban soils of the Ruhr basin, near the cities of Duisburg and Essen, Germany. The main aim of this study was to investigate the occurrence of mono-, di- and trimethylated species of these elements in urban soils. The influence of historical and present land use upon the species content was examined. The distribution of inorganic As, Sb and Sn and their methylated species along the profile depth was investigated. As, Sb and Sn speciation was performed by pH-gradient hydride generation purge and trap gas chromatography, followed by inductively-coupled plasma mass spectrometry (HG-PT-GC/ICP-MS). Species' structures were confirmed by GC-EI/MS-ICP-MS. Monomethylated Sb and As were the dominant species detected: the concentration of these metal(loid) species varied between <0.07-56 microg kg(-1) per dry mass. All dimethylated species and monomethyltin concentrations were between <0.01-7.6 microg kg(-1) per dry mass, and for the trimethylated species of all examined elements, concentrations between <0.001-0.63 microg kg(-1) per dry mass were detected. The highest organometal(loid) concentrations were observed in agricultural soils and garden soils; lower concentrations were found in the soils of abandoned industrial sites (wasteland, primary forest and grassland) and a flood plain soil of the Rhine. This result can be ascribed to both the cultivation and the increased biological activity of the agricultural soils, and the generally higher contamination, the disturbed structure and the artificial substrates (deposits from industrial sources) of the abandoned industrial soils. Due to periodical sedimentation, the flood plain profile was the only one where no depth dependence of organometal(loid) species concentration was detected. The other soil profiles showed a decrease of species content with increasing depth; this was particularly noticeable in soils with a clear change from a horizon with an organic character towards a mineral horizon, i.e. decreasing vitality from profile top to bottom. It is not as yet clear whether the organometal(loid) species are formed in the mineral horizons of the profiles or whether they are displaced from the organic, biologically-active horizons towards the mineral horizons. Field studies revealed that soil parameters like pH, water content or temperature did not correlate significantly with the degree of biomethylation observed. In contrast to the lower in vitro biomethylation efficiency of Sb vs. As in microbial incubations, we consistently detected higher proportions of transformed Sb compounds in situ in soil samples. These data may indicate a need to re-examine the currently accepted model of Sb biogeochemical cycling in the real environment. 相似文献
167.
Mare?L?hmusEmail author Roland?Sandberg Rebecca?L.?Holberton Frank?R.Moore 《Behavioral ecology and sociobiology》2003,54(3):233-239
We examined the relationship between plasma levels of corticosterone and the migratory activity and directional preference of red-eyed vireos during fall migration at the northern coast of the Gulf of Mexico. Corticosterone is thought to play a role in physiological and behavioural processes before, during, and after long-distance migratory flights. An increase in corticosterone at the onset of migratory flights can be expected in birds that are energetically prepared to migrate in a seasonally appropriate southerly direction. Red-eyed vireos ( Vireo olivaceus) were tested in orientation cages under clear twilight skies. Just prior to the orientation experiments, blood was sampled to assay baseline corticosterone levels. Average corticosterone level for all birds was 22.8 ng/ml. Red-eyed vireos with higher than average baseline levels of corticosterone were significantly more active in orientation cages compared to birds with lower levels of corticosterone. Moreover, birds with higher than average levels oriented in a southwesterly direction, which is consistent with a trans-Gulf flight, whereas individuals with levels below average showed a NNW mean direction. Although there was no significant difference in baseline levels of corticosterone between fat and lean birds, individual mass loss between capture and test was negatively correlated with corticosterone levels. Results from this study clearly demonstrate that corticosterone influences departure decisions and the choice of direction during migration. 相似文献
168.
169.
Martin Paulus Monika Altmeyer Roland Klein Armin Hildebrandt Peter Ostapczuk Konstantin Oxynos 《Umweltwissenschaften und Schadstoff-Forschung》1994,6(6):375-383
Ein sinnvoller Einsatz von Akkumulationsindikatoren erfordert zur Qualit?tssicherung neben den vorhandenen Laborstandards
ein anspruchsvolles Probenahmeverfahren, um repr?sentative und reproduzierbate Aussagen über einen Untersuchungsraum treffen
zu k?nnen. Am Beispiel der Regenwürmer wird exemplarisch ein Probenahmeverfahren für landwirtschaftliche R?ume entwickelt
und vorgeführt. Erste Ergebnisse der in den Wurm- und Kotproben gemessenen polyzyklischen aromatischen Kohlenwasserstoffe,
der chlorierten Kohlenwasserstoffe und der Elemente werden dargestellt. Die Schadstoffgehalte der vergleichbaren Wurmproben
belegen, da? es die repr?sentative Probenahmestelle in einem Untersuchungsgebiet nicht gibt. Die Heterogenit?t des Untersuchungsraumes
kann nur durch eine geschichtete Zufallsstichprobe mit einer ausreichenden Anzahl von Einzelproben erfa?t werden. 相似文献
170.
Metal implants are the preferred materials to generate articular prostheses, plates, or bone pegs in orthopedic surgery.
Although titanium and titanium alloys show a relatively good biocompatibility, clinical experience revealed that coating of
the metallic implant surface may increase the biocompatibility. In a search for optimum bone implant surfaces, we determined
polarity and contact angle parameters of a variety of polymers and substances and correlated the findings in a biocompatibility
assay using an in vitro bone cell model. We report that an optimum adherence of SAOS-2 cells to such surfaces and a good vitality
for polymers are characterized by water-based contact angles of 80° and 20° for advancing and receding probes, respectively.
Received: 18 October 1999 / Accepted in revised form: 19 April 2000 相似文献