全文获取类型
收费全文 | 186篇 |
免费 | 20篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 13篇 |
2013年 | 8篇 |
2012年 | 13篇 |
2011年 | 16篇 |
2010年 | 10篇 |
2009年 | 5篇 |
2008年 | 18篇 |
2007年 | 9篇 |
2006年 | 16篇 |
2005年 | 17篇 |
2004年 | 10篇 |
2003年 | 12篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1977年 | 1篇 |
1974年 | 4篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有206条查询结果,搜索用时 468 毫秒
201.
202.
Summary When arsenate-resistant mutants are selected approximately 50 per cent of them are also consitutive for the synthesis of alkaline phosphatase and the Pi-binding protein. Some of these mutants are linked to ilv (phoS
- or phoT
-), others are linked to proC (phoR
-). One of the mutant strains linked to ilv lost the Pi-binding protein (the phoS gene product). Resistance to arsenate, constitutivty for alkaline phosphatase synthesis and loss of the Pi-binding protein occurred pleiotropically by the same phoS
- mutation. 相似文献
203.
204.
Tuo Shi Gaofeng Niu Hagit Kvitt Xinqing Zheng Qiaoyun Qin Danye Sun Zhiliang Ji Dan Tchernov 《Molecular ecology resources》2021,21(1):137-152
Collectively called zooxanthellae, photosynthetic dinoflagellates in the family Symbiodiniaceae are typical endosymbionts that unequivocally mediate coral responses to environmental changes. Symbiodiniaceae are genetically diverse, encompassing at least nine phylogenetically distinct genera (clades A–I). The ribosomal internal transcribed spacer 2 (ITS2) region is commonly utilized for determining Symbiodiniaceae diversity within clades. However, ITS2 is often inadvertently interpreted together with the tailing part of the ribosomal RNA genes (5.8S and 28S or equivalent), leading to unresolved taxonomy and equivocal annotations. To overcome this hurdle, we mined in GenBank and expert reference databases for ITS2 sequences of Symbiodiniaceae having explicit boundaries with adjacent rRNAs. We profiled a Hidden Markov Model of the ITS2‐proximal 5.8S‐28S rRNA interaction, which was shown to facilitate the delimitation of Symbiodiniaceae ITS2 from GenBank, while considerably reducing sequence ambiguity and redundancy in reference databases. The delineation of ITS2 sequences unveiled intra‐clade sequence diversity and inter‐clade secondary structure conservation. We compiled the clean data into a non‐redundant database that archives the largest number of Symbiodiniaceae ITS2 sequences known to date with definite genotype/subclade representations and well‐defined secondary structures. This database provides a fundamental reference catalog for consistent and precise genotyping of Symbiodiniaceae and a tool for automated annotation of user‐supplied sequences. 相似文献
205.
Estrone sulfatase activity in the human brain and estrone sulfate levels in the normal menstrual cycle 总被引:2,自引:0,他引:2
M P Platia M D Fencl K E Elkind-Hirsch J A Canick D Tulchinsky 《Journal of steroid biochemistry》1984,21(3):237-241
When the plasma concentrations of estrone sulfate (E1S) were measured in five menstrual cycles, the highest concentrations were found on the day of LH peak (14.25 nmol/l +/- 2.94 [SE]). Peak levels of E1S were 20 times higher than the highest E2 levels measured (0.769 +/- 0.276 nmol/l). To determine whether E1S can be metabolized by adult and fetal tissues we examined estrone (E1) sulfatase activity in brain and other tissues. E1 Sulfatase activity was present in all tissues studied including adult endometrium, fat and skin. When the rate of sulfatase activity was measured in homogenates of fetal hypothalamus, frontal cortex and pituitary (n = 4), the hypothalamic activity (306.0 +/- 39.1 [SE] pmol/min/mg protein) was significantly higher than that of the frontal cortex (127.4 +/- 19.4, P less than 0.002) or pituitary (193.7 +/- 43.3, P less than 0.03). This was not apparent in the adult (n = 2) where the enzyme activity was similar in the hypothalamus (413.9 +/- 27.3) and frontal cortex (446.3 +/- 82.2) and lower in the pituitary (98.2 +/- 19.2). The Km for E1 sulfatase in the fetal frontal cortex was 28.9 microM. The high E1 sulfatase activity in estrogen responsive target tissues, particularly fetal hypothalamus, accompanied by a large circulating reservoir of E1S, suggest that this enzyme could possibly have a regulatory role in controlling the level of intracellular estrogens and in modulating their intracellular function. 相似文献
206.