全文获取类型
收费全文 | 696篇 |
免费 | 21篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 38篇 |
废物处理 | 28篇 |
环保管理 | 103篇 |
综合类 | 123篇 |
基础理论 | 155篇 |
环境理论 | 4篇 |
污染及防治 | 183篇 |
评价与监测 | 45篇 |
社会与环境 | 37篇 |
灾害及防治 | 8篇 |
出版年
2024年 | 1篇 |
2023年 | 19篇 |
2022年 | 16篇 |
2021年 | 20篇 |
2020年 | 25篇 |
2019年 | 18篇 |
2018年 | 29篇 |
2017年 | 33篇 |
2016年 | 45篇 |
2015年 | 33篇 |
2014年 | 42篇 |
2013年 | 57篇 |
2012年 | 56篇 |
2011年 | 47篇 |
2010年 | 35篇 |
2009年 | 35篇 |
2008年 | 25篇 |
2007年 | 33篇 |
2006年 | 25篇 |
2005年 | 22篇 |
2004年 | 16篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 10篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1981年 | 1篇 |
1972年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有724条查询结果,搜索用时 15 毫秒
471.
472.
473.
474.
475.
Florencia Petracchi Silvina Sisterna Laura Igarzabal Louise Wilkins-Haug 《黑龙江环境通报》2019,39(9):758-780
Congenital heart diseases are a common prenatal finding. The prenatal identification of an associated genetic syndrome or a major extracardiac anomaly helps to understand the etiopathogenic diagnosis. Besides, it also assesses the prognosis, management, and familial recurrence risk while strongly influences parental decision to choose termination of pregnancy or postnatal care. This review article describes the most common genetic diagnoses associated with a prenatal finding of a congenital heart disease and a suggested diagnostic process. 相似文献
476.
477.
478.
479.
480.
Abstract: The deleterious consequences of inbreeding have been well documented. There are, however, few empirical studies that have examined the consequences of restoring heterozygosity and hence the fitness of inbred populations by conducting interpopulation crosses and measuring the performance of later-generation hybrids under field conditions. We conducted interpopulation crosses of 100 m to 2000 km, which spans the range of Chamaecrista fasciculata ( Fabaceae) in eastern North America. We then contrasted the performance of the F1 and later-segregating F3 hybrids with the parental generation. We found almost universal F1 superiority over the parents. The F3 hybrids suffered a loss of fitness compared to the F1 hybrids. The drop off in fitness of the F3 reflects both the loss of heterozygosity and the disruption of coadapted gene complexes. The F3 performance, however, was still often equal to that of the parents, suggesting that heterosis can outweigh the loss of coadaptation except for the longest-distance crosses. In a subset of environments, the F3 performance of long-distance (≥1000 km) interpopulation crosses was less than that of both parents and indicated true outbreeding depression. For C. fasciculata , it appears that crossing populations of up to intermediate distances of hundreds of kilometers has a short-term beneficial effect on progeny performance through F1, and that longer-term effects are not necessarily disruptive of fitness, at least relative to parental performance. The degree of F1 heterosis and F3 outbreeding depression varied between site and year, however, indicating an important role for the environment in the expression of these effects. 相似文献