全文获取类型
收费全文 | 764篇 |
免费 | 49篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 15篇 |
2016年 | 20篇 |
2015年 | 32篇 |
2014年 | 36篇 |
2013年 | 48篇 |
2012年 | 50篇 |
2011年 | 45篇 |
2010年 | 36篇 |
2009年 | 24篇 |
2008年 | 40篇 |
2007年 | 51篇 |
2006年 | 54篇 |
2005年 | 35篇 |
2004年 | 45篇 |
2003年 | 44篇 |
2002年 | 34篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 5篇 |
1997年 | 12篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 2篇 |
1989年 | 7篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1973年 | 4篇 |
1959年 | 1篇 |
排序方式: 共有813条查询结果,搜索用时 203 毫秒
791.
792.
Alessandra Bragonzi Gianfranco Distefano Lorraine D Buckberry Giulia Acerbis Chiara Foglieni Damien Lamotte Gabriele Campi Annie Marc Marco R Soria Nigel Jenkins Lucia Monaco 《Biochimica et Biophysica Acta (BBA)/General Subjects》2000,1474(3):273-282
Chinese hamster ovary (CHO) cells are widely employed to produce glycosylated recombinant proteins. Our group as well as others have demonstrated that the sialylation defect of CHO cells can be corrected by transfecting the α2,6-sialyltransferase (α2,6-ST) cDNA. Glycoproteins produced by such CHO cells display both α2,6- and α2,3-linked terminal sialic acid residues, similar to human glycoproteins. Here, we have established a CHO cell line stably expressing α2,6-ST, providing a universal host for further transfections of human genes. Several relevant parameters of the universal host cell line were studied, demonstrating that the α2,6-ST transgene was stably integrated into the CHO cell genome, that transgene expression was stable in the absence of selective pressure, that the recombinant sialyltransferase was correctly localized in the Golgi and, finally, that the bioreactor growth parameters of the universal host were comparable to those of the parental cell line. A second step consisted in the stable transfection into the universal host of cDNAs for human glycoproteins of therapeutic interest, i.e. interferon-γ and the tissue inhibitor of metalloproteinases-1. Interferon-γ purified from the universal host carried 40.4% α2,6- and 59.6% α2,3-sialic acid residues and showed improved pharmacokinetics in clearance studies when compared to interferon-γ produced by normal CHO cells. 相似文献
793.
794.
Luigi Bisceglia Maria Julia Calonge Luca Dello Strologo Gianfranco Rizzoni Luisa de Sanctis Michele Gallucci Ercole Beccia Xavier Testar Antonio Zorzano Xavier Estivill Leopoldo Zelante Manuel Palacin P. Gasparini Virginia Nunes 《Human genetics》1996,98(4):447-451
A cystinuria disease gene (rBAT) has recently been identified, but evidence strongly suggests that only Type-I cystinuria
is due to mutations in this gene. Sixteen point mutations and a large deletion causing the disease have so far been described
in the rBAT gene sequence. To identify new mutated alleles, genomic DNA was analyzed, after the determination of the entire
genomic structure of the rBAT gene, by RNA-single strand conformation polymorphism analysis, an accurate and sensitive method
able to detect nucleotide changes. Four new point mutations, a large deletion, and a common intragenic polymorphism were detected.
These new mutations increase to 22 the number of mutated alleles so far characterized in rBAT. In addition, the frequency
of 21 mutations was assessed in a sample of accurately defined Type-I cystinuria choromosomes. They account for about 58%
of all Type-I chromosomes, mutation M467T being the most common (0.26).
Received: 15 March 1996 / Revised: 17 May 1996 相似文献
795.
Summary A simple technique for rapid determination of fermentation starters vitality which eliminates the need for determination of viable cells counts is described. The mathematical relationship between cell number and oxygen consumption of eight strains of Saccharomyces cerevisiae was studied. Results confirmed the possibility of utilizing a pO2 probe as an indicator of cell viability for fermentation starter. 相似文献
796.
Gianfranco Menestrina Giovanna Belmonte Valerio Parisi Silvia Morante 《FEMS microbiology letters》1992,105(1-3):19-28
Abstract Staphylococcus aureus α-toxin makes cells and model membranes permeable to ions and uncharged molecules by opening oligomeric pores of uniform size. Its primary sequence reveals peculiar features which give some hints on the structure of the pore. A flexible region separating the toxin into two halves, several amphiphilic β-strands and two amphiphilic α-helices long enough to span the hydrophobic core of the lipid bilayer are predicted. In analogy to bacterial porins, we propose that the inner walls of the pore are, at least in part, built by an amphiphilic β-barrel. The model is consistent with circular dichroism data and with the electrophysiological properties of the pore. Functional information on this toxin were obtained by chemical modification of its four histidine residues. Specific carbethoxylation suggested they have different roles: one is required for specific receptor binding, one for oligomerisation and two for unspecific lipid binding. A tentative assignment of each histidine to its specific role is done on the basis of the structural predictions. A functionally related hemolysin, Aeromonas hydrophyla aerolysin, reveals remarkably similar features including the presence and location of histidines involved in receptor binding and oligomerisation. 相似文献
797.
Mario Milco DElios Mathijs P. Bergman Amedeo Amedei Ben J. Appelmelk Gianfranco Del Prete 《Microbes and infection / Institut Pasteur》2004,6(15):1395
Host specific T-cell response is critical for the outcome of Helicobacter pylori infection. In genetically susceptible individuals, H. pylori can activate gastric CD4+ Th1 cells that recognize cross-reactive epitopes shared by H. pylori proteins and self H+, K+-ATPase, leading to gastric autoimmunity via molecular mimicry. 相似文献
798.
799.
Gianfranco De Pieri Angelo Signor Gian Maria Bonora Claudio Toniolo 《International journal of biological macromolecules》1984,6(1):35-40
A circular dichroism investigation of two β-bend forming, Aib-containing tetrapeptides, with the -Aib-l-Ala- and -l-Ala-Aib- central sequences, occurring in peptaibol antibiotics, blocked at the N-terminal end with the 2,4-dinitrophenyl group and at the C-terminal end with the p-nitroanilino group, is described. A comparison is made with a tetrapeptide containing the -l-Ala-l-Ala- central sequence, also observed in peptaibol antibiotics. The amount of β-bend conformers, determined from the intensities of the exciton couplets arising from the intramolecular interaction of the p-nitroanilino chromophores, has been assessed as a function of the hydrogen-bonding properties of the solvent. The conformational analysis in dimethylsulphoxide has been extended to 1H nuclear magnetic resonance. Some information on the type of β-bend formed has additionally been obtained. The preparation and characterization of the three chromophoric tetrapeptides, along with some analogues and synthetic precursors, are also reported. 相似文献
800.