全文获取类型
收费全文 | 1172篇 |
免费 | 70篇 |
出版年
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 51篇 |
2020年 | 14篇 |
2019年 | 33篇 |
2018年 | 45篇 |
2017年 | 22篇 |
2016年 | 45篇 |
2015年 | 73篇 |
2014年 | 87篇 |
2013年 | 122篇 |
2012年 | 122篇 |
2011年 | 112篇 |
2010年 | 53篇 |
2009年 | 59篇 |
2008年 | 69篇 |
2007年 | 76篇 |
2006年 | 59篇 |
2005年 | 39篇 |
2004年 | 31篇 |
2003年 | 29篇 |
2002年 | 25篇 |
2001年 | 7篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1980年 | 3篇 |
1976年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有1242条查询结果,搜索用时 15 毫秒
41.
Deletion of PsbM in tobacco alters the QB site properties and the electron flow within photosystem II 总被引:1,自引:0,他引:1
Umate P Schwenkert S Karbat I Dal Bosco C Mlcòchová L Volz S Zer H Herrmann RG Ohad I Meurer J 《The Journal of biological chemistry》2007,282(13):9758-9767
Photosystem II, the oxygen-evolving complex of photosynthetic organisms, includes an intriguingly large number of low molecular weight polypeptides, including PsbM. Here we describe the first knock-out of psbM using a transplastomic, reverse genetics approach in a higher plant. Homoplastomic Delta psbM plants exhibit photoautotrophic growth. Biochemical, biophysical, and immunological analyses demonstrate that PsbM is not required for biogenesis of higher order photosystem II complexes. However, photosystem II is highly light-sensitive, and its activity is significantly decreased in Delta psbM, whereas kinetics of plastid protein synthesis, reassembly of photosystem II, and recovery of its activity are comparable with the wild type. Unlike wild type, phosphorylation of the reaction center proteins D1 and D2 is severely reduced, whereas the redox-controlled phosphorylation of photosystem II light-harvesting complex is reversely regulated in Delta psbM plants because of accumulation of reduced plastoquinone in the dark and a limited photosystem II-mediated electron transport in the light. Charge recombination in Delta psbM measured by thermoluminescence oscillations significantly differs from the 2/6 patterns in the wild type. A simulation program of thermoluminescence oscillations indicates a higher Q(B)/Q(-)(B) ratio in dark-adapted mutant thylakoids relative to the wild type. The interaction of the Q(A)/Q(B) sites estimated by shifts in the maximal thermoluminescence emission temperature of the Q band, induced by binding of different herbicides to the Q(B) site, is changed indicating alteration of the activation energy for back electron flow. We conclude that PsbM is primarily involved in the interaction of the redox components important for the electron flow within, outward, and backward to photosystem II. 相似文献
42.
43.
Cutrona G Boffa LC Mariani MR Matis S Damonte G Millo E Roncella S Ferrarini M 《Oligonucleotides》2007,17(1):146-150
The present study aims to evaluate the antigenicity of a PNA complementary to the Emu sequence (PNAEmu) with cancer therapeutic potential properties in Burkitt's lymphoma (BL). In BL cells, the c-myc oncogene is repositioned next to the Emu enhancer of the immunoglobulin (Ig) locus, due to chromosomal translocation, and up-regulated. PNAEmu linked to a nuclear localization signal peptide was shown specifically to block c-myc hyperexpression by inhibiting cell growth in vitro and in vivo. Recently, we reported that the administration of PNAEmu to mice, following inoculation with BL cells, hinders tumor growth without toxic effects. To investigate the potential use of PNAEmu in clinical applications further, we tested its antigenicity. Mice were inoculated with an emulsion of free PNA or PNA crosslinked to the immunogenic carrier keyhole limpet hemocyanin (KLH) with Freund's adjuvant. Antibodies to free PNA were undetected, whereas both IgG and IgM antibodies to PNA-KLH were detected in mouse serum 28 and 38 days after inoculation. 相似文献
44.
Chiara Salvesi Stefania Silvi Dennis Fiorini Serena Scortichini Gianni Sagratini Francesco A. Palermo Renato De Leone Nadaniela Egidi Lorella Fatone Carlo Cifani Amedeo Amedei Francesca Scocchera Mara Morici Beatrice Gatto Fausto Mannucci Valerio Valeriani Marco Malavasi Sara Servili Andrea Casula Andrea Cresci Ivano Corradetti Francesco Carpi Matteo Picciolini Maria Magdalena Coman Maria Cristina Verdenelli 《Journal of applied microbiology》2022,133(5):2941-2953
45.
Edoardo Pasolli Francesco Asnicar Serena Manara Moreno Zolfo Nicolai Karcher Federica Armanini Francesco Beghini Paolo Manghi Adrian Tett Paolo Ghensi Maria Carmen Collado Benjamin L. Rice Casey DuLong Xochitl C. Morgan Christopher D. Golden Christopher Quince Curtis Huttenhower Nicola Segata 《Cell》2019,176(3):649-662.e20
46.
Serena Ricci Federica Pinto Adelaide Auletta Antonio Giordano Alfonso Giovane Giuliana Settembre Mariarosaria Boccellino Silvia Boffo Angelina Di Carlo Marina Di Domenico 《Journal of cellular biochemistry》2019,120(5):6813-6819
The most prevalent malignancy in the oral cavity is represented by oral squamous cell carcinoma, an aggressive disease mostly detected in low-income communities. This neoplasia is mostly diffused in older men particularly exposed to risk factors such as tobacco, alcohol, and a diet rich in fatty foods and poor in vegetables. In oral squamous cell carcinoma, a wide range of matrix-cleaving proteinases are involved in extracellular matrix remodeling of cancer microenvironment. In particular, matrix metalloproteinases (MMPs) represent the major and most investigated protagonists. Owing to their strong involvement in malignant pathologies, MMPs are considered the most promising new biomarkers in cancer diagnosis and prognosis. The interest in studying MMPs in oral cancer biology is also owing to their prominent role in epithelial-to-mesenchymal transition (EMT). EMT is an intricate process involving different complex pathways. EMT-related proteins are attractive diagnostic biomarkers that characterize the activation of biological events that promote cancer's aggressive expansion. Different antioncogenic natural compounds have been investigated to counteract oral carcinogenesis, with the scope of obtaining better clinical results and lower morbidity. In particular, we describe the role of different nutraceuticals used for the regulation of MMP-related invasion and proliferation of oral cancer cells. 相似文献
47.
Shana V. Stoddard Colin L. Welsh Maggie M. Palopoli Serena D. Stoddard Mounika P. Aramandla Riya M. Patel Hong Ma Laurence H. Beck Jr 《Proteins》2019,87(2):136-145
The thrombospondin type-1 domain containing 7A (THSD7A) protein is known to be one of the antigens responsible for the autoimmune disorder idiopathic membranous nephropathy. The structure of this antigen is currently unsolved experimentally. Here we present a homology model of the extracellular portion of the THSD7A antigen. The structure was evaluated for folding patterns, epitope site prediction, and function was predicted. Results show that this protein contains 21 extracellular domains and with the exception of the first two domains, has a regular repeating pattern of TSP-1-like followed by F-spondin-like domains. Our results indicate the presence of a novel Trp-ladder sequence of WxxxxW in the TSP-1-like domains. Of the 21 domains, 18 were shown to have epitope binding sites as predicted by epitopia. Several of the F-spondin-like domains have insertions in the canonical TSP fold, most notably the coiled coil region in domain 4, which may be utilized in protein-protein binding interactions, suggesting that this protein functions as a heparan sulfate binding site. 相似文献
48.
Characterization of the complex locus of bean encoding polygalacturonase-inhibiting proteins reveals subfunctionalization for defense against fungi and insects 总被引:8,自引:0,他引:8 下载免费PDF全文
D'Ovidio R Raiola A Capodicasa C Devoto A Pontiggia D Roberti S Galletti R Conti E O'Sullivan D De Lorenzo G 《Plant physiology》2004,135(4):2424-2435
49.
50.
The effects of peroxynitrite on hyaluronan has been studied by using an integrated spectroscopical approach, namely electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), and mass spectrometry (MS). The reaction has been performed with the polymer, the tetrasaccharide oligomer as well as with the monosaccharides N-acetylglucosamine and glucuronic acid. The outcome of the presence of molecular oxygen and carbon dioxide has been also evaluated. Although 1H-NMR and ESI-MS experiments did not revealed peroxynitrite-mediated modification of hyaluronan as well as of related saccharides, from spin-trapping EPR experiments it was concluded that peroxynitrite induce the formation of C-centered carbon radicals, most probably by the way of its hydroxyl radical-like reactivity. These EPR data support the oxidative pathway involved in the degradation of hyaluronan, a probable event in the development and progression of rheumatoid arthritis. 相似文献