全文获取类型
收费全文 | 377篇 |
免费 | 2篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 23篇 |
环保管理 | 46篇 |
综合类 | 156篇 |
基础理论 | 61篇 |
环境理论 | 3篇 |
污染及防治 | 70篇 |
评价与监测 | 13篇 |
社会与环境 | 6篇 |
灾害及防治 | 1篇 |
出版年
2022年 | 4篇 |
2020年 | 4篇 |
2018年 | 7篇 |
2017年 | 11篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2013年 | 22篇 |
2012年 | 9篇 |
2011年 | 14篇 |
2010年 | 10篇 |
2009年 | 15篇 |
2008年 | 12篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 9篇 |
2004年 | 4篇 |
2003年 | 8篇 |
2002年 | 16篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 6篇 |
1996年 | 13篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1987年 | 3篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 8篇 |
1971年 | 3篇 |
1969年 | 3篇 |
1965年 | 5篇 |
1964年 | 3篇 |
1963年 | 5篇 |
1962年 | 3篇 |
1961年 | 6篇 |
1960年 | 4篇 |
1959年 | 3篇 |
1958年 | 5篇 |
1957年 | 6篇 |
1954年 | 5篇 |
排序方式: 共有387条查询结果,搜索用时 812 毫秒
171.
172.
173.
174.
Kelly KE Wagner DA Lighty JS Sarofim AF Rogers CF Sagebiel J Zielinska B Arnott WP Palmer G 《Journal of the Air & Waste Management Association (1995)》2003,53(3):273-282
Diluted exhaust from selected military aircraft ground-support equipment (AGE) was analyzed for particulate mass, elemental carbon (EC) and organic carbon (OC), SO4(2-), and size distributions. The experiments occurred at idle and load conditions and utilized a chassis dynamometer. The selected AGE vehicles operated on gasoline, diesel, and JP-8. These military vehicles exhibited concentrations, size distributions, and emission factors in the same range as those reported for nonmilitary vehicles. The diesel and JP-8 emission rates for PM ranged from 0.092 to 1.1 g/kg fuel. The EC contributed less and the OC contributed more to the particulate mass than reported in recent studies of vehicle emissions. Overall, the particle size distribution varied significantly with engine condition, with the number of accumulation mode particles and the count median diameter (CMD) increasing as engine load increased. The SO4(2-) analyses showed that the distribution of SO4(2-) mass mirrored the distribution of particle mass. 相似文献
175.
176.
Boeije GM Wagner JO Koormann F Vanrolleghem PA Schowanek DR Feijtel TC 《Chemosphere》2000,40(3):255-265
By means of GREAT-ER (Geo-Referenced Regional Exposure Assessment Tool for European Rivers) aquatic chemical fate simulations can be performed for river basins. To apply the resulting digital maps with local (river stretch specific) predicted concentrations in regional aquatic exposure and risk assessment, the output has to be aggregated to a (single) value representative of exposure in the catchment. Two spatially aggregated PEC definitions are proposed for this purpose: PECinitial (unweighted aggregation of concentrations just downstream of wastewater emissions) and PECcatchment (weighted aggregation of all average stretch concentrations). These PECs were tested using simulations for two pilot study catchments (Calder and Went, UK). This confirmed the theoretical considerations which led to the definitions, and it illustrated the need for weighting to resolve scale-dependencies. 相似文献
177.
Sensory brain areas in three families of deep-sea fish (slickheads, eels and grenadiers): comparison of mesopelagic and demersal species 总被引:1,自引:0,他引:1
H. -J. Wagner 《Marine Biology》2002,141(5):807-817
The sensory brain areas of a sample of <100 deep-sea fish species were studied, and the relative volumes of the olfactory
bulb, optic tectum, octavolateral area and gustatory area were determined. In the absence of direct observations on the behaviour
of this ichthyofauna these data allow deductions to be made about the kinds of sensory modalities used preferentially in the
deep-sea environment. Here, members of three families are compared that have representatives living on or near the sea floor
(“demersal”) and in the open water between 200 and 1.000 m (mesopelagic). The findings indicate that both regions present
fish with rich and diverse sensory environments. While vision emerges as the dominant sense of the mesopelagic realm, olfaction
seems more important on or near the bottom of the sea. However, other sensory modalities supplement these senses in species-specific
patterns. Considerations of the phyletic relationships indicate different degrees of pervasiveness. Whilst in slickheads the
dominance of vision appears to be a family-related trait, a similar relationship is not found in either eels or grenadiers.
By contrast, the common trait in these two families seems to be the greater adaptability to the environment.
Published online: 21 August 2002 相似文献
178.
Peter Fabian 《Die Naturwissenschaften》1976,63(6):273-279
179.
180.
Samira Veiga Ravaiano Wagner Faria Barbosa Lúcio Antônio Campos Gustavo Ferreira Martins 《Die Naturwissenschaften》2018,105(7-8):48
The insect immune system faces various challenges; particularly in social bees, caste system and age polyethism expose individuals to numerous environmental and working conditions. However, little is known about how cellular defenses in social bees may be organized to respond to a variety of immune challenges. Here, we describe the morphological features and the total and differential counts of hemocytes in different female classes (newly emerged workers, nurses, foragers, and virgin queens) of the eusocial stingless bee Melipona quadrifasciata. Granulocytes and prohemocytes were, respectively, the most and the least abundant cells among all classes of females. Furthermore, there were more prohemocytes in virgin queens than in foragers. The total number of hemocytes was smaller in foragers, whereas the largest number was observed in nurse workers. This reduced amount of hemocytes in foragers might allow energy savings to perform colony activities such as foraging and defense. Foragers also had the biggest hemocytes (either prohemocytes, granulocytes, or plasmatocytes) in comparison to the other classes of females, which might have arisen as a compensation for the reduction in number of these cells during aging. These results suggest that profiles of hemocytes of M. quadrifasciata vary according to the caste and age of this eusocial bee. 相似文献