全文获取类型
收费全文 | 168篇 |
免费 | 11篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 9篇 |
2014年 | 6篇 |
2013年 | 2篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 8篇 |
2005年 | 2篇 |
2004年 | 5篇 |
2002年 | 2篇 |
2001年 | 4篇 |
1999年 | 3篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1985年 | 8篇 |
1984年 | 2篇 |
1983年 | 6篇 |
1982年 | 5篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有179条查询结果,搜索用时 15 毫秒
21.
Mahfoud M Sukumaran S Hülsmann P Grieger K Niederweis M 《The Journal of biological chemistry》2006,281(9):5908-5915
MspA is the major porin of Mycobacterium smegmatis mediating the exchange of hydrophilic solutes across the outer membrane (OM). It is the prototype of a new family of octameric porins with a single central channel of 9.6 nm in length and consists of two hydrophobic beta-barrels of 3.7 nm in length and a more hydrophilic, globular rim domain. The length of the hydrophobic domain of MspA does not match the thicknesses of mycobacterial OMs of 5-12 nm as derived from electron micrographs. Further, the membrane topology of MspA is unknown as it is for any other mycobacterial OM protein. We used MspA as a molecular ruler to define the boundaries of the OM of M. smegmatis by surface labeling of single cysteine mutants. Seventeen mutants covered the surface of the rim domain and were biotinylated with a membrane-impermeable reagent. The label efficiencies in vitro were remarkably similar to the predicted accessibilities of the cysteines. By contrast, six of these mutants were protected from biotinylation in M. smegmatis cells. Tryptophan 21 defines a horizontal plane that dissects the surface-exposed versus the membrane-protected residues of MspA. The 8 phenylalanines at position 99 form a ring at the periplasmic end of the hydrophobic beta-barrel domain. These results indicated that (i) the membrane boundaries of MspA are defined by aromatic girdles as in porins of Gram-negative bacteria and (ii) loops and a 3.4-nm long part of the hydrophilic rim domain are embedded into the OM of M. smegmatis. This is the first report suggesting that elements other than hydrophobic alpha-helices or beta-sheets are integrated into a lipid membrane. 相似文献
22.
RP Tucker K Drabikowski JF Hess J Ferralli R Chiquet-Ehrismann JC Adams 《BMC evolutionary biology》2006,6(1):60-17
Background
Tenascins are a family of glycoproteins found primarily in the extracellular matrix of embryos where they help to regulate cell proliferation, adhesion and migration. In order to learn more about their origins and relationships to each other, as well as to clarify the nomenclature used to describe them, the tenascin genes of the urochordate Ciona intestinalis, the pufferfish Tetraodon nigroviridis and Takifugu rubripes and the frog Xenopus tropicalis were identified and their gene organization and predicted protein products compared with the previously characterized tenascins of amniotes. 相似文献23.
24.
25.
26.
27.
JC. Brisset F. Gazeau C. Corot N. Nighoghossian Y. Berthezène E. Canet-Soulas M. Wiart 《IRBM》2018,39(2):93-102
Background
Inflammation is a share process in atherosclerosis and stroke and is thought to be a key player in the evolution of these diseases. Ten years ago, inflammation imaging with magnetic resonance imaging (MRI) was considered very promising for both pre-clinical and clinical studies of atherosclerosis and stroke.Contribution
We report here contributions to the field of inflammation imaging with USPIO-enhanced MRI. The goal was to investigate the life cycle of USPIOs in the body, and how the MRI signal has been impacted during their bio-interactions and bioprocessing. Those mechanisms were applied to pre-clinical longitudinal studies of inflammation in atherosclerosis and at the acute stage of ischemic stroke thus allowing the monitoring of treatment effects.Conclusion
This review presents the contribution of the collaborative research project under the “TecSan” grant from the French Research Agency (ANR) as well as pre-clinical and clinical perspectives of USPIO's inflammation MRI in atherosclerosis and stroke. 相似文献28.
Nonneutral evolution of tandem repeats in the mitochondrial DNA control region of lagomorphs 总被引:7,自引:0,他引:7
Casane D; Dennebouy N; de Rochambeau H; Mounolou JC; Monnerot M 《Molecular biology and evolution》1997,14(8):779-789
The mitochondrial DNA of the European rabbit (Oryctolagus cuniculus)
contains a tandem array of 153-bp repeats in the vicinity of the
replication origin of the H-stand. Variation among molecules in the number
of these repeats results in inter- and intraindividual length polymorphism
(heteroplasmy). Generally, in an individual, one predominant molecular type
is observed, the others representing a low percentage of the mtDNA content.
At the tissue level, we observe a particular distribution of this
polymorphism in the gonads compared with liver, kidneys, or brain, implying
a relationship between the differentiation status of the cells and the
types of new mtDNA molecules which appear and accumulate during lifetime.
Similar tandem repeats were also found in the mtDNA noncoding region of
European hares (Lepus europaeus), a cottontail (Sylvilagus floridanus), and
a pika (Ochotona rufescens). The lengths and the sequences of these units
evolve rapidly and in a concerted way, but the number of repeats is
maintained in a narrow range, and an internal 20-bp segment is highly
conserved. Constraints restrict the evolution of the primary sequence of
these repeated units, the number of which is probably controlled by a
stabilizing selection.
相似文献
29.
Bone marrow stromal cells are multipotent and have been shown to differentiate into a wide variety of mesenchymal cell types in vivo. In this study we tested the ability of bovine bone marrow stromal cells to contribute to the development of porcine skeletal muscle tissue. Fetal pigs were injected early in gestation with bone marrow stem cells originating from slaughtered steers. After approximately forty days of development the fetuses were harvested and sections of their skeletal muscle were analyzed for the presence of bovine cells. PCR was used to detect bovine DNA present in DNA extracted from the fetal pig skeletal muscle. We also used a PRINS (Oligonucleotide Primed In- Situ Synthesis) protocol to confirm the presence of bovine cells within the porcine skeletal muscle tissue sections. The results of both assays indicate that bovine bone marrow stromal cells can participate in the development of porcine skeletal muscle. This study helps to demonstrate the potential that bone marrow stromal cells have to contribute to advances in animal biotechnology and medicine. 相似文献
30.
Distinguishing morphologically cryptic taxa, by definition, requires genetic data such as DNA sequences. However, DNA sequences may not be obtained easily for taxa from remote sites. Here we provide the details of a high-resolution melt-curve-based method using taxon-specific primers that can distinguish two taxa of Adélie penguins, and that will be usable in Antarctica when combined with some of the newly developed field-deployable thermal cyclers. We suggest that the wider adoption of field-deployable polymerase-chain-reaction-based techniques will enable faster assignation of haplotype to individuals in situ, and so allow the targeting of observations and sample collection to specimens relevant to the research question. Targeting individuals will also reduce the need to repeatedly handle animals and reduce the time and travel required to complete field work. 相似文献