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871.
872.
This work demonstrates that Acinetobacter radioresistens strain S13 during the growth on medium supplemented with long‐chain alkanes as the sole energy source expresses almA gene coding for a Baeyer‐Villiger monooxygenase (BVMO) involved in alkanes subterminal oxidation. Phylogenetic analysis placed the sequence of this novel BVMO in the same clade of the prodrug activator ethionamide monooxygenase (EtaA) and it bears only a distant relation to the other known class I BVMO proteins. In silico analysis of the 3D model of the S13 BVMO generated by homology modelling also supports the similarities with EtaA by binding ethionamide to the active site. In vitro experiments carried out with the purified enzyme confirm that this novel BVMO is indeed capable of typical Baeyer‐Villiger reactions as well as oxidation of the prodrug ethionamide. 相似文献
873.
874.
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
875.
876.
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
877.
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
878.
Tom J. Savenije Dengyang Guo Valentina M. Caselli Eline M. Hutter 《Liver Transplantation》2020,10(26)
The unprecedented rise in the power conversion efficiency of solar cells based on metal halide perovskites (MHPs) has led to enormous research effort to understand their photophysical properties. The progress made in understanding the mobility and recombination of photogenerated charge carriers from nanosecond to microsecond time scales, monitored using electrodeless transient photoconductivity techniques, is reviewed. In addition, a kinetic model to obtain rate constants from transient data recorded using a wide range of laser intensities is presented. For various MHPs the temperature dependence of the mobilities and recombination rates are evaluated. Furthermore, it is shown how these rate constants can be used to predict the upper limit for the open‐circuit voltage Voc of the corresponding device. Finally, the photophysical properties of MHPs that are not yet fully understood are explored, and recommendations for future research directions are made. 相似文献
879.
880.
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