全文获取类型
收费全文 | 18625篇 |
免费 | 149篇 |
国内免费 | 153篇 |
专业分类
安全科学 | 390篇 |
废物处理 | 769篇 |
环保管理 | 2147篇 |
综合类 | 4029篇 |
基础理论 | 4666篇 |
环境理论 | 6篇 |
污染及防治 | 4486篇 |
评价与监测 | 1200篇 |
社会与环境 | 1188篇 |
灾害及防治 | 46篇 |
出版年
2022年 | 114篇 |
2021年 | 129篇 |
2019年 | 108篇 |
2018年 | 307篇 |
2017年 | 313篇 |
2016年 | 485篇 |
2015年 | 285篇 |
2014年 | 372篇 |
2013年 | 1109篇 |
2012年 | 790篇 |
2011年 | 812篇 |
2010年 | 498篇 |
2009年 | 583篇 |
2008年 | 682篇 |
2007年 | 730篇 |
2006年 | 665篇 |
2005年 | 880篇 |
2004年 | 1028篇 |
2003年 | 898篇 |
2002年 | 532篇 |
2001年 | 653篇 |
2000年 | 408篇 |
1999年 | 312篇 |
1998年 | 189篇 |
1997年 | 215篇 |
1996年 | 226篇 |
1995年 | 236篇 |
1994年 | 235篇 |
1993年 | 219篇 |
1992年 | 198篇 |
1991年 | 213篇 |
1990年 | 201篇 |
1989年 | 174篇 |
1988年 | 169篇 |
1987年 | 156篇 |
1986年 | 153篇 |
1985年 | 150篇 |
1984年 | 169篇 |
1983年 | 167篇 |
1982年 | 172篇 |
1981年 | 145篇 |
1980年 | 132篇 |
1979年 | 126篇 |
1978年 | 135篇 |
1977年 | 115篇 |
1976年 | 104篇 |
1975年 | 109篇 |
1974年 | 120篇 |
1971年 | 100篇 |
1967年 | 102篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
251.
252.
253.
254.
255.
P. Götz 《Die Naturwissenschaften》1971,58(11):569-570
256.
257.
Dr M. Buscaglia L. Ghisoni M. Bellotti A. M. Marconi P. Zamperini L. Stripparo A. Molinari M. G. Grimoldi F. Rossella 《黑龙江环境通报》1995,15(1):17-19
We present a technique to aspirate amniotic fluid from both sacs in biamniotic twin pregnancies using a single abdominal insertion with a spinal needle. It was successful in 48 out of 55 cases of biamniotic twin pregnancies referred to our perinatal unit between 1985 and 1994. The single insertion technique was used when the inter-amniotic membrane was clearly evident and two separate free amniotic fluid pools could be reached by the operator with a single puncture. An adequate amount of amniotic fluid was sampled from both sacs to make a cytogenetic diagnosis in all cases. There were four fetuses with trisomy 21 in three twin pregnancies. In two cases, only one twin was affected whilst the co-twin was normal, so that a selective feticide was performed. No miscarriages due to genetic amniocentesis were reported. After 1990, all genetic amniocenteses in biamniotic twin pregnancies (except for one case due to late booking) were performed between 14 and 15 weeks of gestation and with all cases except one, it was possible to sample both twins by a single puncture. We suggest that early amniocentesis (14–15 weeks) by a single abdominal puncture could be a reliable and safe alternative to first-trimester chorionic villus sampling in twin pregnancies. 相似文献
258.
Jan Gustafsson Göran Annerén Ulla-Britt Ericsson Lars Svanberg Sten A. Ivarsson 《黑龙江环境通报》1995,15(5):451-454
The observation that thyroid disease is frequent in mothers of children with Down syndrome (DS) has suggested that maternal thyroid antibodies could be a factor predisposing to trisomy 21 in their offspring. In this study, the incidences of thyroglobulin (Tg) and thyroid peroxidase (TPO) antibodies were analysed with a sensitive solid-phase immunosorbent radioassay in sera from 29 mothers giving birth to children with trisomy 21 and 87 control mothers. The serum samples were collected at delivery. There was no statistical difference regarding the proportion of thyroid antibodies (against Tg and/or TPO) in the two groups. Thyroid antibodies were detected in 6/29 (20.7 per cent) of the DS mothers and in 23/87 (26.4 per cent) of the control mothers. Among the women with thyroid antibodies, 4/6 (66.7 per cent) of the DS mothers and 12/23 (52 per cent) of the control mothers had antibodies against both Tg and TPO. There was no increase in the relative risk of having a child with DS if the titre of either Tg or TPO antibodies or both were positive, i.e. ≥ 1/5. The results indicate that the presence of thyroid antibodies in the serum of a pregnant woman has no prognostic value for the birth of an infant with DS. 相似文献
259.
Linda?Anderson-BerryEmail author David?King 《Mitigation and Adaptation Strategies for Global Change》2005,10(3):367-392
Community mitigation of hazard impact requires hazard knowledge and preparedness on the part of the members of diverse and
complex communities. Longitudinal research in the tropical cyclone prone north of Australia has gathered extensive datasets
on community awareness, preparedness and knowledge, in order to contribute to education campaigns and mitigation strategies.
Data have been used to identify issues of vulnerability to cyclones and capacity to deal with the hazard. This has been developed
as a community vulnerability and capacity model that may be applied to diverse communities in order to assess levels of capability
to mitigate and deal with the cyclone hazard. The model is presented here in a simplified form as its development is evolving
and ongoing. 相似文献
260.
Ten out of the 12 new EU members, used to belong to the so-called “former eastern block”, with a post WWII environmental policy radically different from the tendencies followed in Western Europe. The lack of conservation regulations has resulted in a rather harmful industrialization, regarding natural resources and environmental quality. While air pollution transfer is a phenomenon of transboundary level, there is a particular interest in examining the contribution of the new EU member states to the environmental pressure faced by the older member states and vice versa. The current study utilises the official data for almost 20 years published by the European Monitoring and Evaluation Program concerning the transboundary transfer of NOx and SO2 in order to analyse the situation and discuss the present and future environmental policy regarding air pollution. 相似文献