全文获取类型
收费全文 | 30923篇 |
免费 | 750篇 |
国内免费 | 5579篇 |
专业分类
安全科学 | 1360篇 |
废物处理 | 1565篇 |
环保管理 | 3432篇 |
综合类 | 10660篇 |
基础理论 | 7036篇 |
环境理论 | 6篇 |
污染及防治 | 9586篇 |
评价与监测 | 1545篇 |
社会与环境 | 1343篇 |
灾害及防治 | 719篇 |
出版年
2023年 | 285篇 |
2022年 | 789篇 |
2021年 | 666篇 |
2020年 | 511篇 |
2019年 | 573篇 |
2018年 | 750篇 |
2017年 | 872篇 |
2016年 | 1029篇 |
2015年 | 1092篇 |
2014年 | 1505篇 |
2013年 | 2860篇 |
2012年 | 1697篇 |
2011年 | 1965篇 |
2010年 | 1485篇 |
2009年 | 1467篇 |
2008年 | 1696篇 |
2007年 | 1606篇 |
2006年 | 1482篇 |
2005年 | 1106篇 |
2004年 | 996篇 |
2003年 | 1065篇 |
2002年 | 962篇 |
2001年 | 1095篇 |
2000年 | 895篇 |
1999年 | 753篇 |
1998年 | 660篇 |
1997年 | 567篇 |
1996年 | 560篇 |
1995年 | 528篇 |
1994年 | 502篇 |
1993年 | 406篇 |
1992年 | 392篇 |
1991年 | 309篇 |
1990年 | 321篇 |
1989年 | 292篇 |
1988年 | 238篇 |
1987年 | 203篇 |
1986年 | 183篇 |
1985年 | 180篇 |
1984年 | 207篇 |
1983年 | 196篇 |
1982年 | 196篇 |
1981年 | 191篇 |
1980年 | 138篇 |
1979年 | 155篇 |
1978年 | 134篇 |
1977年 | 118篇 |
1975年 | 122篇 |
1974年 | 117篇 |
1972年 | 134篇 |
排序方式: 共有10000条查询结果,搜索用时 264 毫秒
61.
62.
V. Nataf M. V. Senat M. Albert L. Bidat P. de Mazancourt J. Roume L. Allard D. Le Tessier Y. Ville J. Selva 《黑龙江环境通报》2002,22(8):675-680
Male phenotype associated with a 45,X karyotype is an infrequent finding. We present a case diagnosed prenatally on amniocentesis performed for maternal age. The male phenotype was associated with a translocation of a distal part of Yp including the pseudoautosomal SHOX gene and SRY gene on the short arm of a chromosome 21. By DNA analysis we could show that the X chromosome was of maternal origin and that the breakpoint was in interval 3 of the Y chromosome. Mechanisms and genetic counselling are discussed based on a review of published cases of 45,X and XX males. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
63.
64.
分析简单地拉伸、压缩和扭转的情况时,应力状态能容易地被确定.但是,实际上在金属加工过程中材料是承受复杂的应力状态,在模具——工件接触面上增加有摩擦力.而且,这些应力和摩擦力一般地沿着接触面变化.准确的计算或预测载荷、力、应力和温度,不但对设计适宜的设备是重要的,而且对研究工艺期间材料的变化过程也是重要的.本文将讨论材料变形过程中所运用的主要分析方法及其优缺点. 相似文献
65.
66.
67.
G. D. Kataev 《Russian Journal of Ecology》2005,36(6):421-426
The effect of industrial air pollution on natural small mammal populations has been studied in the northern taiga subzone of the boreal forest zone. The results of long-term monitoring have been used to demonstrate the possibility of predicting changes in the main population and community characteristics of the animal species studied as dependent on the degree of anthropogenic impact. 相似文献
68.
M Mora R Skiles B McKinney M Paredes D Buckler D Papoulias D Klein 《Environmental pollution (Barking, Essex : 1987)》2002,116(1):169-176
Peregrine falcons (Falco peregrinus) have been recorded nesting in Big Bend National Park, Texas, USA and other areas of the Chihuahuan Desert since the early 1900s. From 1993 to 1996, peregrine falcon productivity rates were very low and coincided with periods of low rainfall. However, low productivity also was suspected to be caused by environmental contaminants. To evaluate potential impacts of contaminants on peregrine falcon populations, likely avian and bat prey species were collected during 1994 and 1997 breeding seasons in selected regions of western Texas, primarily in Big Bend National Park. Tissues of three peregrine falcons found injured or dead and feathers of one live fledgling also were analyzed. Overall, mean concentrations of DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene], a metabolite of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane], were low in all prey species except for northern rough-winged swallows (Stelgidopteryx serripennis, mean = 5.1 microg/g ww). Concentrations of mercury and selenium were elevated in some species, up to 2.5 microg/g dw, and 15 microg/g dw, respectively, which upon consumption could seriously affect reproduction of top predators. DDE levels near 5 microg/g ww were detected in carcass of one peregrine falcon found dead but the cause of death was unknown. Mercury, selenium, and DDE to some extent, may be contributing to low reproductive rates of peregrine falcons in the Big Bend region. 相似文献
69.
70.