全文获取类型
收费全文 | 4727篇 |
免费 | 38篇 |
国内免费 | 25篇 |
专业分类
安全科学 | 61篇 |
废物处理 | 182篇 |
环保管理 | 166篇 |
综合类 | 2089篇 |
基础理论 | 859篇 |
环境理论 | 6篇 |
污染及防治 | 992篇 |
评价与监测 | 257篇 |
社会与环境 | 161篇 |
灾害及防治 | 17篇 |
出版年
2022年 | 56篇 |
2021年 | 51篇 |
2019年 | 40篇 |
2018年 | 77篇 |
2017年 | 72篇 |
2016年 | 94篇 |
2015年 | 71篇 |
2014年 | 122篇 |
2013年 | 216篇 |
2012年 | 144篇 |
2011年 | 127篇 |
2010年 | 132篇 |
2009年 | 139篇 |
2008年 | 162篇 |
2007年 | 179篇 |
2006年 | 136篇 |
2005年 | 126篇 |
2004年 | 109篇 |
2003年 | 129篇 |
2002年 | 90篇 |
2001年 | 95篇 |
2000年 | 83篇 |
1999年 | 84篇 |
1998年 | 61篇 |
1997年 | 57篇 |
1996年 | 38篇 |
1995年 | 51篇 |
1994年 | 58篇 |
1991年 | 38篇 |
1990年 | 41篇 |
1989年 | 34篇 |
1985年 | 33篇 |
1979年 | 39篇 |
1977年 | 33篇 |
1969年 | 36篇 |
1968年 | 33篇 |
1967年 | 58篇 |
1966年 | 50篇 |
1965年 | 63篇 |
1964年 | 64篇 |
1963年 | 65篇 |
1962年 | 57篇 |
1961年 | 65篇 |
1960年 | 55篇 |
1959年 | 65篇 |
1958年 | 65篇 |
1957年 | 76篇 |
1956年 | 49篇 |
1955年 | 53篇 |
1954年 | 48篇 |
排序方式: 共有4790条查询结果,搜索用时 46 毫秒
541.
542.
Der vorliegende überblick, der sich mit den haupts?chlichen Problembereichen der Umwelt in der Landwirtschaft befa?t, macht
deutlich, da? in manchen F?llen wirksame und sofort verwirklichbare L?sungsans?tze bestehen, die mit geringfügigen, regelnden
Eingriffen die Konflikte zwischen Landwirtschaft und Umwelt entsch?rfen k?nnen. Solche L?sungen sind umso tragf?higer, je
breiter und damit wettbewerbsneutraler sie verwirklicht werden und je mehr sie alle Umweltfolgesch?den in Produktionskosten
ausdrücken. 相似文献
543.
Iniencephaly is a rare and lethal congenital malformation of the neural tube characterized by occipital bone defect, cervical dysraphism, fixed retroflexion of the fetal head and severe lordosis of the cervicothoracic spine. The etiology is unknown. Prenatally diagnosed cases of iniencephaly are rare because careful and early ultrasonographic evaluation is necessary. We present three cases of iniencephaly prenatally diagnosed by sonography at 20–22 weeks' gestation in which therapeutic abortion was induced. The sonographic findings were compatible with the postmortem findings. The present cases of iniencephaly were found to carry unusual associated malformations such as two lobes in the right lung and chorangiosis of the placenta. Only hypoplastic lungs have been reported by previous authors. We also studied the 677C→T mutation on the methylenetetrahydrofolate reductase gene in the parents in one of the present cases. The mother was found to be heterozygous for the 677CT polymorphism. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
544.
Agnès Guichet Stéphane Triau Catherine Lépinard Chantal Esculapavit Florence Biquard Philippe Descamps Férechté Encha-Razavi Dominique Bonneau 《黑龙江环境通报》2004,24(10):828-832
We report an interstitial deletion of chromosome 3q26-q28 in a fetus in which anophthalmia had been detected prenatally. FISH analysis, using BAC clones encompassing the SOX2 locus, showed that SOX2 gene was involved in the chromosomal breakpoint of the deletion. This case confirms that haploinsufficiency for SOX2 plays a crucial role in human eye development and emphasizes the necessity of careful chromosomal analysis, including FISH analysis of the 3q region, in case of prenatal discovery of anophthalmia. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
545.
546.
Denis Meuthen Ingolf P. Rick Timo Thünken Sebastian A. Baldauf 《Die Naturwissenschaften》2012,99(12):1063-1066
Many animal species are able to perceive light wavelengths beyond those visible to humans. While numerous species are additionally sensitive to short wavelengths (UV), long wavelengths such as the near-infrared spectrum (NIR) are supposed to be unsuitable for visual perception. Here, we experimentally show that under exclusive NIR illumination, the cichlid fish Pelvicachromis taeniatus displays a clear foraging response towards NIR reflecting prey. Additional control experiments without prey indicate that the observed behavior is not a mere response to the NIR environment. These results give first evidence for NIR visual sensitivity in a functional context and thus challenge the current view about NIR perception. 相似文献
547.
548.
选取嘉兴市秀洲区和海宁市为研究对象,以乡镇区划为研究单元,采用综合源强估算法和GIS软件,对处理设施的氨氮(NH3-N)、总磷(TP)、化学需氧量(COD)排放强度进行定量估算和空间分析.结果表明,秀洲区处理设施的NH3-N和COD排放强度高于海宁市,而TP排放强度与海宁市差不多.秀洲区内,洪合镇各污染物的排放强度均最高;海宁市内,盐官镇NH3-N排放强度最高,许村镇TP和COD排放强度最高.采用因子分析法和加权指数法计算排污权重,再结合生态敏感性评价和环境功能区划,筛选出运维和监管优先控制区.秀洲区内,洪合镇、王江泾镇、油车港镇被划分为优先控制区,该优先控制区内处理设施数量占比27.87%,排污权重占比72.42%,通过重点监管17.66%的设施,可监管秀洲区59.98%的污染物排放.海宁市内,长安镇、许村镇、海洲街道、盐官镇、袁花镇被划分为优先控制区,该优先控制区内设施数量占比69.10%,排污权重占比71.23%,通过重点监管16.85%的设施,可监管海宁市43.54%的污染物排放.研究结果可为提高设施的运维监管效率提供技术支撑. 相似文献
549.
Stefan Leichsenring Dieter Lenoir Antonius Kettrup Gerd Mützenich 《Environmental Sciences Europe》1996,8(4):197-206
The 17th BlmSchV fixed the emission limit of 0.1 ng TE/mn 3 for PCDD/F’s produced as a result of waste- and special waste incinerators. This article introduces the different measures implemented to uphold this limit, and discusses their advantages and disadvantages. Methods of optimising the incineration conditions are among the primary measures. Different geometry’s for conventional oven incineration rooms were discussed, and an effective modernisation method was introduced (Temelli nozzles). The chemical and technical basis of an often discussed gasification method, as well as the characteristics of three specialised techniques (Coke Burn technique, Thermo-Select technique and Noell-DBI technique) are explained in this article. Alongside the secondary measures of hot-dust filtration and inhibition being added to the washers in an attempt to achieve PCDD/F adsorption. The most important tertiary measures, namely the SCR technique, along with a variety of coke adsorption techniques are introduced, with their advantages and disadvantages. New techniques such as DeDioxin and Medisorbon are also addressed. 相似文献
550.
Traffic related platinum deposits on, or near to, the roads. Platinum accumulation was studied using the method of standardised culture of grass (Lolium multiflorum) at locations with different traffic exposure in the region of Munich. Grass cultures from 6 locations with high traffic exposure, and 3 reference locations far away from traffic emissions, were analysed in 1992 and 1993. The results show a good indication of the platinum emissions byLolium multiflorum. The platinum concentrations rose with the increasing traffic. They diminished with growing distance from the verge of the road. The highest average platinum concentrations were measured at locations close to highly frequented urban roads, in the range 0.8 to 2.9 μg/kg dm. The average platinum concentration at locations far from emissions was found in the range of 0.17 to 0.51 μg/kg dm in 1992 and 1993. The good correlation between the platinum concentrations in grass cultures and the concentrations of other traffic-related elements, like antimony, chromium and lead, verifies the dependence of platinum accumulation from traffic. 相似文献