全文获取类型
收费全文 | 246篇 |
免费 | 21篇 |
国内免费 | 1篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 12篇 |
2013年 | 12篇 |
2012年 | 11篇 |
2011年 | 10篇 |
2010年 | 13篇 |
2009年 | 11篇 |
2008年 | 6篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 10篇 |
2004年 | 15篇 |
2003年 | 11篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1985年 | 3篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 3篇 |
1968年 | 4篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 4篇 |
1945年 | 1篇 |
排序方式: 共有268条查询结果,搜索用时 15 毫秒
101.
Background
Estimators of free energies are routinely used to judge the quality of protein structural models. As these estimators still present inaccuracies, they are frequently evaluated by discriminating native or native-like conformations from large ensembles of so-called decoy structures. 相似文献102.
Luo Q Kang Q Si W Jiang W Park JK Peng Y Li X Luu HH Luo J Montag AG Haydon RC He TC 《The Journal of biological chemistry》2004,279(53):55958-55968
Osteoblast lineage-specific differentiation of mesenchymal stem cells is a well regulated but poorly understood process. Both bone morphogenetic proteins (BMPs) and Wnt signaling are implicated in regulating osteoblast differentiation and bone formation. Here we analyzed the expression profiles of mesenchymal stem cells stimulated with Wnt3A and osteogenic BMPs, and we identified connective tissue growth factor (CTGF) as a potential target of Wnt and BMP signaling. We confirmed the microarray results, and we demonstrated that CTGF was up-regulated at the early stage of BMP-9 and Wnt3A stimulations and that Wnt3A-regulated CTGF expression was beta-catenin-dependent. RNA interference-mediated knockdown of CTGF expression significantly diminished BMP-9-induced, but not Wnt3A-induced, osteogenic differentiation, suggesting that Wnt3A may also regulate osteoblast differentiation in a CTGF-independent fashion. However, constitutive expression of CTGF was shown to inhibit both BMP-9- and Wnt3A-induced osteogenic differentiation. Exogenous expression of CTGF was shown to promote cell migration and recruitment of mesenchymal stem cells. Our findings demonstrate that CTGF is up-regulated by Wnt3A and BMP-9 at the early stage of osteogenic differentiation, which may regulate the proliferation and recruitment of osteoprogenitor cells; however, CTGF is down-regulated as the differentiation potential of committed pre-osteoblasts increases, strongly suggesting that tight regulation of CTGF expression may be essential for normal osteoblast differentiation of mesenchymal stem cells. 相似文献
103.
104.
Sedimentation-equilibrium and other physicochemical studies on the lysine-rich fraction of calf thymus histones 总被引:2,自引:2,他引:0
1. The lysine-rich fraction (Ia+Ib, or f1) of calf thymus histones was isolated as the sulphate by acid extraction. 2. Sedimentation-equilibrium measurements with interference optics showed that this fraction was monodisperse with a molecular weight of 19500±2000. 3. The `apparent molecular weight' calculated from the sedimentation-equilibrium studies varied markedly with concentration. The large second virial coefficient implied by such variation was attributed to the very high charge/mass ratio of this relatively small protein. Estimates of the charge were made from the values of this virial coefficient. 4. The very large value of the virial coefficient explains anomalies in the earlier reports of the molecular weight of this histone and also why the z-average molecular weight can appear to be lower than the weight-average molecular weight. 5. The differences of the specific refractive increments, and the partial specific volumes, between dialysed and undialysed solutions of this histone fraction could also be attributed to its high molecular charge, which was estimated from these differences and agreed, within the expected limits, with the value deduced from the second virial coefficient. 6. Sedimentation-velocity measurements combined with the known molecular weight imply that lysine-rich histone has a high frictional ratio and an extended shape. Optical-rotatory-dispersion measurements indicated that it had a low helical content. 相似文献
105.
The Maternal CCAAT Box Transcription Factor Which Controls GATA-2 Expression Is Novel and Developmentally Regulated and Contains a Double-Stranded-RNA-Binding Subunit
下载免费PDF全文
![点击此处可从《Molecular and cellular biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
106.
Zacharia Mtema Joel Changalucha Sarah Cleaveland Martin Elias Heather M. Ferguson Jo E. B. Halliday Daniel T. Haydon Gurdeep Jaswant Rudovick Kazwala Gerry F. Killeen Tiziana Lembo Kennedy Lushasi Alpha D. Malishee Rebecca Mancy Matthew Maziku Eberhard M. Mbunda Geofrey J. M. Mchau Roderick Murray-Smith Kristyna Rysava Khadija Said Maganga Sambo Elizabeth Shayo Lwitiko Sikana Sunny E Townsend Honorathy Urassa Katie Hampson 《PLoS medicine》2016,13(4)
107.
Mark Hebblewhite Daniel T. Haydon 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2010,365(1550):2303-2312
In the past decade, ecologists have witnessed vast improvements in our ability to collect animal movement data through animal-borne technology, such as through GPS or ARGOS systems. However, more data does not necessarily yield greater knowledge in understanding animal ecology and conservation. In this paper, we provide a review of the major benefits, problems and potential misuses of GPS/Argos technology to animal ecology and conservation. Benefits are obvious, and include the ability to collect fine-scale spatio-temporal location data on many previously impossible to study animals, such as ocean-going fish, migratory songbirds and long-distance migratory mammals. These benefits come with significant problems, however, imposed by frequent collar failures and high cost, which often results in weaker study design, reduced sample sizes and poorer statistical inference. In addition, we see the divorcing of biologists from a field-based understanding of animal ecology to be a growing problem. Despite these difficulties, GPS devices have provided significant benefits, particularly in the conservation and ecology of wide-ranging species. We conclude by offering suggestions for ecologists on which kinds of ecological questions would currently benefit the most from GPS/Argos technology, and where the technology has been potentially misused. Significant conceptual challenges remain, however, including the links between movement and behaviour, and movement and population dynamics. 相似文献
108.
Tomasz W. Pyrcz Haydon Warren-Gash Jadwiga Lorenc-Brudecka Dieuwko?Knoop Philippe Oremans Szabolcs Sáfián 《ZooKeys》2013,(298):1-37
Updated data on the distribution, ecology and taxonomy of Euphaedra cyparissa (Cramer) and Euphaedra sarcoptera (Butler) are presented. Three new subspecies of Euphaedra cyparissa and one of Euphaedra sarcoptera are described and their geographic distribution is presented. The monophyly of the genus Euphaedra sensu Hecq is assessed based on morphological, in particular male and female genitalia, and behavioural traits. Possible evolutionary reasons for the convergence of colour pattern between the sympatric subspecies of Euphaedra cyparissa and Euphaedra sarcoptera are discussed. 相似文献
109.
Wenping Luo Linghuan Zhang Bo Huang Hongmei Zhang Yan Zhang Fugui Zhang Panpan Liang Qiuman Chen Qianyu Cheng Dongmei Tan Yi Tan Jinlin Song Tianyu Zhao Rex C. Haydon Russell R. Reid Hue H Luu Michael J. Lee Mostafa El Dafrawy Ping Ji Tong-Chuan He Liming Gou 《Journal of cellular and molecular medicine》2021,25(5):2666-2678
Teeth arise from the tooth germ through sequential and reciprocal interactions between immature epithelium and mesenchyme during development. However, the detailed mechanism underlying tooth development from tooth germ mesenchymal cells (TGMCs) remains to be fully understood. Here, we investigate the role of Wnt/β-catenin signalling in BMP9-induced osteogenic/odontogenic differentiation of TGMCs. We first established the reversibly immortalized TGMCs (iTGMCs) derived from young mouse mandibular molar tooth germs using a retroviral vector expressing SV40 T antigen flanked with the FRT sites. We demonstrated that BMP9 effectively induced expression of osteogenic markers alkaline phosphatase, collagen A1 and osteocalcin in iTGMCs, as well as in vitro matrix mineralization, which could be remarkably blunted by knocking down β-catenin expression. In vivo implantation assay revealed that while BMP9-stimulated iTGMCs induced robust formation of ectopic bone, knocking down β-catenin expression in iTGMCs remarkably diminished BMP9-initiated osteogenic/odontogenic differentiation potential of these cells. Taken together, these discoveries strongly demonstrate that reversibly immortalized iTGMCs retained osteogenic/odontogenic ability upon BMP9 stimulation, but this process required the participation of canonical Wnt signalling both in vitro and in vivo. Therefore, BMP9 has a potential to be applied as an efficacious bio-factor in osteo/odontogenic regeneration and tooth engineering. Furthermore, the iTGMCs may serve as an important resource for translational studies in tooth tissue engineering. 相似文献
110.