全文获取类型
收费全文 | 115篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 1篇 |
环保管理 | 13篇 |
综合类 | 49篇 |
基础理论 | 15篇 |
污染及防治 | 19篇 |
评价与监测 | 12篇 |
社会与环境 | 2篇 |
灾害及防治 | 2篇 |
出版年
2022年 | 2篇 |
2020年 | 3篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 4篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 4篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1984年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1963年 | 2篇 |
1962年 | 2篇 |
1959年 | 3篇 |
1958年 | 2篇 |
1957年 | 2篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1951年 | 1篇 |
1950年 | 1篇 |
1946年 | 1篇 |
1942年 | 1篇 |
1934年 | 1篇 |
1932年 | 1篇 |
1931年 | 1篇 |
1930年 | 1篇 |
1929年 | 1篇 |
1924年 | 1篇 |
排序方式: 共有117条查询结果,搜索用时 31 毫秒
31.
The recently developed type transfer function (TTF) simulation approach was applied to generate a regional-scale nonpoint-source ground water vulnerability assessment for the San Joaquin Valley, California. The computationally comparatively inexpensive TTF approach produces quantitative estimates of contaminant concentrations for large regional scales through characteristic functions based on different soil textures and their leaching properties. The TTF simulations employed an extensive soil and recharge database to estimate atrazine (1-chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine) concentrations at a compliance depth of 3 m resulting from a surface application. Two different sets of TTFs with two different levels of upscaling were used for spatially uniform and distributed recharge estimates. Results show that estimated atrazine concentrations can be related to soil survey information. Areas with high potential vulnerability to atrazine leaching were found for soils with low organic carbon content and sandy loam and loam textures. Travel times for atrazine peak concentrations to the compliance depth ranged from 350 to 730 d. The extent of areas with estimated atrazine concentrations above the maximum contaminant level was less extensive when uniform annual recharge values were used. Simulated TTF concentrations were highest for eastern Fresno County, a vulnerability pattern that is also supported by field observations. The TTF modeling approach is shown to be a useful tool for quantitative pesticide leaching estimates at regional scales significantly larger than those of previous studies. 相似文献
32.
Duarte CM Agustí S Wassmann P Arrieta JM Alcaraz M Coello A Marbà N Hendriks IE Holding J García-Zarandona I Kritzberg E Vaqué D 《Ambio》2012,41(1):44-55
The Arctic marine ecosystem contains multiple elements that present alternative states. The most obvious of which is an Arctic Ocean largely covered by an ice sheet in summer versus one largely devoid of such cover. Ecosystems under pressure typically shift between such alternative states in an abrupt, rather than smooth manner, with the level of forcing required for shifting this status termed threshold or tipping point. Loss of Arctic ice due to anthropogenic climate change is accelerating, with the extent of Arctic sea ice displaying increased variance at present, a leading indicator of the proximity of a possible tipping point. Reduced ice extent is expected, in turn, to trigger a number of additional tipping elements, physical, chemical, and biological, in motion, with potentially large impacts on the Arctic marine ecosystem. 相似文献
33.
34.
Abnormal pregnancy sonogram and chromosomal anomalies: Four years' experience with rapid karyotyping
Over a four-year period, 140 pregnancies with different malformations detected by ultrasound were examined cytogenetically. Gestational age ranged from 13 to 36 weeks. Twenty-six fetuses (18.6 per cent) had abnormal karyotypes, including trisomies, triploidy, monosomy X, and structural anomalies. Similar malformations were found in fetuses with different chromosomal anomalies, indicating that the types of malformations are not specific for particular chromosomal anomalies. Chromosomal analysis was performed on amniotic fluid culture and by direct karyotyping of placental biopsies. Direct karyotyping is suggested to be the most rapid approach, especially if sonographic anomalies are detected close to the 24th week of gestation, shortly before delivery, and in cases of significant oligohydramnios. 相似文献
35.
Ralf Dillert Matthias Brandt Iris Fornefett Ulrike Siebers Detlef Bahnemann 《Chemosphere》1995,30(12):2333-2341
The photocatalytic degradation of 2,4,6-trinitrotoluene and ten other nitroaromatic compounds in aerated TiO2 suspensions has been studied. The following order of reactivity was observed: nitrotoluenes > nitrobenzene > dinitrotoluenes . dinitrobenzenes > 2,4,6-trinitrotoluene > 1,3,5-trinitrobenzene, which reflects the known influence of nitro groups towards the attack of electrophilic reagents on the aromatic molecule. 相似文献
36.
Disinfection of surfaces by photocatalytic oxidation with titanium dioxide and UVA light 总被引:11,自引:0,他引:11
Kühn KP Chaberny IF Massholder K Stickler M Benz VW Sonntag HG Erdinger L 《Chemosphere》2003,53(1):71-77
Particularly in microbiological laboratories and areas in intensive medical use, regular and thorough disinfection of surfaces is required in order to reduce the numbers of bacteria and to prevent bacterial transmission. The conventional methods of disinfection with wiping are not effective in the longer term, cannot be standardized, are time- and staff-intensive and use aggressive chemicals. Disinfection with hard ultraviolet C (UVC) light is usually not satisfactory, as the depth of penetration is inadequate and there are occupational medicine risks. Photocatalytic oxidation on surfaces coated with titanium dioxide (TiO2) might offer a possible alternative. In the presence of water and oxygen, highly reactive OH-radicals are generated by TiO2 and mild ultraviolet A (UVA). These radicals are able to destroy bacteria, and may therefore be effective in reducing bacterial contamination. Direct irradiation with UVC however can produce areas of shadow in which bacteria are not inactivated. Using targeted light guidance and a light-guiding sheet (out of a UVA-transmittant, Plexiglas, for example), as in the method described in the present study, bacterial inactivation over the entire area is possible. The effectiveness of the method was demonstrated using bacteria relevant to hygiene such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecium. For these bacteria, a reduction efficiency (RE) more than 6log10 steps in 60 min was observed. Using Candida albicans, a RE of 2log10 steps in 60 min was seen. Light and scanning electron microscopic examinations suggest that the germ destruction achieved takes place through direct damage to cell walls caused by OH-radicals. 相似文献
37.
Marlies H?rdtlein Martin Kaltschmitt und Iris Lewandowski 《Umweltwissenschaften und Schadstoff-Forschung》1998,10(3):135-140
Zusammenfassung Teil I gibt einen überblick über den Ursprung und die Entwicklung des Begriffes “Nachhaltigkeit” im allgemeinen und für die
Landwirtschaft im speziellen. Demnach wird Nachhaltigkeit zwar unter ?kologischen, sozialen und ?konomischen Aspekten diskutiert;
eine allgemein anerkannte Definition des Begriffes existiert bisher jedoch weder für die jeweiligen Einzelaspekte noch unter
Zusammenführung aller drei Aspekte. Dies erschwert die Ermittlung und Umsetzung der Nachhaltigkeit in der Praxis.
Ausgehend von der Begriffsentwicklung und den wesentlichen heute definierten Begriffsinhalten wird deshalb für eine nachhaltige
Pflanzenproduktion aus prim?r ?kologischer Sicht eine Definition vorgeschlagen. Sie dient als Grundlage für einen methodischen
Ansatz, der eine Operationalisierung und damit eine Umsetzung der Nachhaltigkeit der Pflanzenproduktion in der Praxis erm?glichen
soll (?Teil II).
相似文献
38.
39.
40.
K. Andrée J. Bartels F. K. Rubbert Hans Götte R. Harder R. Harder 《Die Naturwissenschaften》1951,38(10):239-240