全文获取类型
收费全文 | 2264篇 |
免费 | 25篇 |
国内免费 | 25篇 |
专业分类
安全科学 | 73篇 |
废物处理 | 75篇 |
环保管理 | 331篇 |
综合类 | 487篇 |
基础理论 | 465篇 |
环境理论 | 3篇 |
污染及防治 | 606篇 |
评价与监测 | 134篇 |
社会与环境 | 121篇 |
灾害及防治 | 19篇 |
出版年
2023年 | 23篇 |
2022年 | 21篇 |
2021年 | 34篇 |
2020年 | 29篇 |
2019年 | 34篇 |
2018年 | 64篇 |
2017年 | 62篇 |
2016年 | 74篇 |
2015年 | 86篇 |
2014年 | 94篇 |
2013年 | 116篇 |
2012年 | 100篇 |
2011年 | 146篇 |
2010年 | 122篇 |
2009年 | 129篇 |
2008年 | 119篇 |
2007年 | 124篇 |
2006年 | 108篇 |
2005年 | 77篇 |
2004年 | 98篇 |
2003年 | 56篇 |
2002年 | 75篇 |
2001年 | 78篇 |
2000年 | 42篇 |
1999年 | 25篇 |
1998年 | 29篇 |
1997年 | 28篇 |
1996年 | 25篇 |
1995年 | 38篇 |
1994年 | 21篇 |
1993年 | 8篇 |
1992年 | 19篇 |
1991年 | 30篇 |
1990年 | 14篇 |
1989年 | 18篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 11篇 |
1981年 | 10篇 |
1979年 | 9篇 |
1970年 | 6篇 |
1969年 | 4篇 |
1965年 | 4篇 |
1960年 | 4篇 |
1958年 | 3篇 |
1954年 | 3篇 |
排序方式: 共有2314条查询结果,搜索用时 250 毫秒
1.
2.
Christophe Pélabon Jean-Michel Gaillard Anne Loison Christine Portier 《Behavioral ecology and sociobiology》1995,37(5):311-319
We examined data on sex-specific differences in neonatal weight, litter size and adult female body weight in 32 populations of polygynous ungulates of 18 different species to test for the existence of a trade-off between sex-biased maternal care and the total amount of maternal expenditure. This corresponds to an extension of the hypothesis of Byers and Moodie (1990) that sex-biased maternal care is limited by a high level of maternal expenditure. We did not find any relationship between sex-biased care and two measures of total maternal expenditure. We highlighted high intraspecific variability in sex-biased care and very low intraspecific variability in total maternal expenditure. Even when this between-population variability in sex-biased care was accounted for, no relationship between sex-biased maternal care and maternal expenditure was detected. Apart from difficulties in finding suitable measures for both variables, two other reasons may account for the lack of a relationship between sex-biased maternal care and total maternal expenditure. Firstly, male offspring seem to be more affected than female offspring by harsh environmental conditions. This may lead to the variation observed in the extent of sex-specific differences in birth weight within a single species. If we assume that for a given maternal expenditure reproductive costs incurred by mothers are highest during harsh conditions, this could indicate the existence of a trade-off between sex-biased maternal care and maternal expenditure at the intra-specific level, thereby supporting the Byers and Moodie hypothesis. Secondly, polygyny is only a poor predictor of sex-biased care and factors such as compensatory growth or extended periods of growth may be expected to modify predictions for different species. Thus, environmental conditions and relative effects of maternal care on male and female lifetime reproductive success are better predictors of sex-biased care than total maternal expenditure.Communicated by P.M. Kappeler 相似文献
3.
4.
5.
Thierry Rousseau Nicole Laurent Christel Thauvin-Robinet Stéphanie Lionnais Christine Durand Laurence Faivre Paul Sagot 《黑龙江环境通报》2002,22(8):692-696
Fraser syndrome (MIM 219000) is a rare disorder of autosomal recessive inheritance, characterized by the association of cryptophthalmos, syndactyly and genital abnormalities. Here we report on two cases of Fraser syndrome (cryptophthalmos syndrome) in a non-consanguineous couple, with variable expression in echographic, clinical and autopsy findings. Furthermore, we highlight the difficulties in prenatal diagnosis of Fraser syndrome. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
6.
7.
Stéphanie Couvreur-Lionnais Thierry Rousseau Nicole Laurent Christel Thauvin-Robinet Eve Senet-Lacombe Anne Lise Delezoïde Francine Mugneret Christine Durand Laurence Faivre Paul Sagot 《黑龙江环境通报》2005,25(2):172-175
Juberg–Hayward syndrome is a rare autosomal recessive syndrome characterised by the association of growth retardation, microcephaly, cleft lip and palate, and thumb and radial ray abnormalities. To date, no prenatal cases have been reported. Here, we report on the first prenatal case of Juberg–Hayward syndrome. The diagnosis was established following fetopathological study. Besides the cardinal features of the syndrome, this prenatal case was remarkable for the severity of the short arm malformation and by the finding of big toe agenesis and cerebral abnormalities including hydrocephalus, agenesis of corpus callosum, and cerebellar hypoplasia. We conclude that the diagnosis of Juberg–Hayward syndrome can be discussed prenatally following ultrasound diagnosis of the association of intrauterine growth restriction, microcephaly, thumb/radial anomalies, and cleft lip/palate. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
8.
9.
10.
Hofschreuder P van der Meulen W Heeres P Slanina S 《Journal of environmental monitoring : JEM》1999,1(2):143-147
Passive samplers provide an excellent opportunity to perform indicative measurements or establish a dense network of measuring sites. A drawback compared with conventional active measuring methods is the larger spread of results. This variation can, to a large extent, be attributed to the influence of temperature, sampler geometry and wind on sampling results. A proper design of sampler geometry and optimum choice of draught shield can reduce the influence of wind velocity on a badge type sampler to less than 10%. Wire mesh screens prove to be inadequate in damping turbulence. Filters give good results. Attention should be paid to the size and isolation value of the walls of the sampler to prevent thermal updrafts occurring within the sampler. Tube type samplers are less influenced by wind, provided that turbulence is prevented from influencing diffusion within the sampler. 相似文献