全文获取类型
收费全文 | 36311篇 |
免费 | 399篇 |
国内免费 | 298篇 |
专业分类
安全科学 | 1057篇 |
废物处理 | 1394篇 |
环保管理 | 4927篇 |
综合类 | 5476篇 |
基础理论 | 10364篇 |
环境理论 | 23篇 |
污染及防治 | 9547篇 |
评价与监测 | 2233篇 |
社会与环境 | 1754篇 |
灾害及防治 | 233篇 |
出版年
2022年 | 260篇 |
2021年 | 237篇 |
2019年 | 264篇 |
2018年 | 504篇 |
2017年 | 480篇 |
2016年 | 717篇 |
2015年 | 595篇 |
2014年 | 837篇 |
2013年 | 2683篇 |
2012年 | 1058篇 |
2011年 | 1558篇 |
2010年 | 1291篇 |
2009年 | 1310篇 |
2008年 | 1563篇 |
2007年 | 1651篇 |
2006年 | 1463篇 |
2005年 | 1264篇 |
2004年 | 1214篇 |
2003年 | 1205篇 |
2002年 | 1153篇 |
2001年 | 1552篇 |
2000年 | 1089篇 |
1999年 | 668篇 |
1998年 | 522篇 |
1997年 | 525篇 |
1996年 | 538篇 |
1995年 | 591篇 |
1994年 | 526篇 |
1993年 | 463篇 |
1992年 | 497篇 |
1991年 | 453篇 |
1990年 | 473篇 |
1989年 | 498篇 |
1988年 | 415篇 |
1987年 | 352篇 |
1986年 | 316篇 |
1985年 | 365篇 |
1984年 | 346篇 |
1983年 | 391篇 |
1982年 | 380篇 |
1981年 | 321篇 |
1980年 | 288篇 |
1979年 | 321篇 |
1978年 | 259篇 |
1977年 | 230篇 |
1976年 | 235篇 |
1975年 | 228篇 |
1974年 | 212篇 |
1973年 | 212篇 |
1972年 | 226篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
891.
L. E. M. Niers J. A. M. Smeitink J. M. F. Trijbels R. C. A. Sengers A. J. M. Janssen L. P. van den Heuvel 《黑龙江环境通报》2001,21(10):871-880
NADH:ubiquinone oxidoreductase (complex I of the mitochondrial respiratory chain) deficiency is a severe disorder with an often early fatal outcome. Prenatal diagnosis for complex I defects currently relies mainly on biochemical assays of complex I in fetal tissues such as chorionic villi (CV), and is only in a minority of cases possible by means of mutational analysis of nuclear-encoded genes of complex I. We report on our experience to date with prenatal diagnosis in pregnancies at risk for complex I deficiency. We measured complex I activity in native CV and/or cultured CV in 23 pregnancies in 15 families. In accordance with the results of the investigations in CV, 15 children were born clinically unaffected. Two prenatally diagnosed unaffected fetuses and two prenatally diagnosed affected fetuses were lost prematurely with spontaneous or provoked abortions, respectively. Two affected children were born (prenatally found to be affected). In two pregnancies a discrepancy between native and cultured cells was found. We conclude that prenatal diagnosis for complex I deficiency can be reliably performed. Pitfalls were encountered in using cultured CV as a result of maternal cell contamination (MCC). Future research on pathogenic nuclear mutations underlying complex I deficiency will extend the possibilities for prenatal diagnosis at the molecular level. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
892.
893.
894.
We thank B. Zentgraf for his basic and constructive ideas and his field support, R. Andi Abdoerrachman for logistic and technical support and E. Shimokawa, Kagoshima University, for providing a charcoal sample from Kutai National Park. We thank P. Becker-Heidmann, Isotope Dating Laboratory, University of Hamburg, for his immediate 14C-dating by Liquid Scintillation Counting, and Chr. Goedicke, Rathgen Research Laboratory, Staatliche Museen Preussischer Kulturbesitz Berlin, for immediate TL dating. M. A. Gill, C.S.I.R.O. Canberra, has critically reviewed this paper. This research was sponsored by the Volkswagen Foundation. 相似文献
895.
896.
897.
A. Betz S. Koritnig H. J. Oel A. Schneider E. Ackermann Hans Schaefer 《Die Naturwissenschaften》1955,42(18):518-520
898.
899.
900.