全文获取类型
收费全文 | 665篇 |
免费 | 2篇 |
国内免费 | 6篇 |
专业分类
系统科学 | 9篇 |
教育与普及 | 2篇 |
理论与方法论 | 20篇 |
现状及发展 | 66篇 |
研究方法 | 105篇 |
综合类 | 384篇 |
自然研究 | 87篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 10篇 |
2012年 | 43篇 |
2011年 | 147篇 |
2010年 | 28篇 |
2009年 | 4篇 |
2008年 | 50篇 |
2007年 | 49篇 |
2006年 | 44篇 |
2005年 | 57篇 |
2004年 | 59篇 |
2003年 | 54篇 |
2002年 | 48篇 |
2001年 | 1篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有673条查询结果,搜索用时 15 毫秒
671.
A total of 66 algal species representing 32 genera were recovered from soils of 10 sites in the Catavi?a region of the Central Desert of Baja California, Mexico. The most common species encountered were the cyanophytes Nostoc commune and Schizothrix calcicola , the chlorophyte Myrmecia astigmatica , and the diatoms Hantzschia amphioxys, Hantzschia amphyoxys f. capitata, Luticola cohnii, Luticola mutica , and Pinnularia borealis var. scalarts . Nine species not found in any previous studies of North American desert soils were present in our study sites, including 3 taxa new to science: Cylindrocystis brebissonii var. deserti , var. nov.; Elakatothrix obtusata , sp. nov.; and Fasciculochloris mexicana , sp. nov. Attempts to correlate species composition with soil chemical and physical parameters were unsuccessful apart from a pH effect on cyanobacterial distribution. Overall composition of the soil algal community in the Catavi?a region is distinct from other desert sites we have studies, although some cosmopolitan desert soil taxa were present. 相似文献
672.
Samuel H. Wilson William A. Beard David D. Shock Vinod K. Batra Nisha A. Cavanaugh Rajendra Prasad Esther W. Hou Yuan Liu Kenjiro Asagoshi Julie K. Horton Donna F. Stefanick Padmini S. Kedar Michael J. Carrozza Aya Masaoka Michelle L. Heacock 《Cellular and molecular life sciences : CMLS》2010,67(21):3633-3647
Base excision repair (BER) can protect a cell after endogenous or exogenous genotoxic stress, and a deficiency in BER can render a cell hypersensitive to stress-induced apoptotic and necrotic cell death, mutagenesis, and chromosomal rearrangements. However, understanding of the mammalian BER system is not yet complete as it is extraordinarily complex and has many back-up processes that complement a deficiency in any one step. Due of this lack of information, we are unable to make accurate predictions on therapeutic approaches targeting BER. A deeper understanding of BER will eventually allow us to conduct more meaningful clinical interventions. In this review, we will cover historical and recent information on mammalian BER and DNA polymerase β and discuss approaches toward development and use of small molecule inhibitors to manipulate BER. With apologies to others, we will emphasize results obtained in our laboratory and those of our collaborators. 相似文献
673.