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41.
Application of the Deoxyribonucleic Acid/Ribonucleic Acid Hybridization Technique in Bdellovibrio as a Model for Studying Ribonucleic Acid Turnover in Host-Parasite Systems
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The kinetics of host ribonucleic acid (RNA) degradation and its resynthesis into Bdellovibrio-specific polyribonucleotides has been studied. The kinetics of RNA turnover was followed during a one-step synchronous growth cycle of Bdellovibrio growing within 32PO4-labeled Escherichia coli host cells. The species of labeled RNA present at any given time was ascertained through the specificity of the deoxyribonucleic acid (DNA)/RNA hybridization technique. At nearsaturating levels of RNA and at zero time, 7% of the host DNA sequences and only 0.04% of the Bdellovibrio DNA became hybridized with 32P-labeled host cell RNA (greater than 99% host specific). At the end of the burst, 98% of the labeled RNA sequences were specific for Bdellovibrio DNA. About 74% of the initial labeled host cell RNA became turned over into Bdellovibrio-specific sequences. We provide data indicating that host cell ribosomal RNA is assimilated by Bdellovibrio. Degradation of host cell RNA occurs in a gradual fashion over most of the Bdellovibrio developmental growth cycle. This application of the DNA/RNA hybridization technique and its general concept should be of value in elucidating the kinetics of nucleic acid turnover in other types of host-parasite systems. 相似文献
42.
When hemocyanin is added to a black lipid film, the conductance increases in discrete steps. For negative potentials the single step conductance is constant, but for positive potentials the step conductance appears to decrease as the potential increases. At high positive potentials the conductance fluctuates between several levels. These data suggest that, in lipid membranes, hemocyanin conducts ions through discrete channels. The voltage-dependent conductance observed at high levels of conductance seems to be a consequence of the properties of the conductance of the single channel. 相似文献
43.
Elena Roura Ma Pilar Almajano Ma Lourdes Mata Bilbao Cristina Andrés-Lacueva Ramon Estruch 《Free radical research》2013,47(8):943-949
Associations between cocoa consumption in humans, excreted metabolites and total antioxidant capacity (TAC) have been scarcely investigated. The aims of the study were to investigate the epicatechin (( ? )-Ec) metabolites excreted in urine samples after an intake of 40 g of cocoa powder along with the TAC of these urine samples and the relation between both the analyses. Each of the 21 volunteers received two interventions, one with a polyphenol-rich food (PRF) and one with a polyphenol-free food (PFF) in a randomized cross-over study. Urine samples were taken before and during 24 h at 0–6, 6–12 and 12–24 h periods after test intake. The excreted ( ? )-Ec metabolites and the TAC were determined in urine samples by LC-MS/MS and TEAC assay, respectively. The maximum excretion of ( ? )-Ec metabolites and the maximum TAC value were observed in urine samples excreted between 6 and 12 h after PRF consumption. Significance of TAC increase was found in urine samples excreted during 0–6 and 6–12 h (66.6 and 72.67%, respectively, with respect to the 0 h). 相似文献
44.
Jean Armengaud Agnès Delaunay-Moisan Jean-Yves Thuret Eelco van Anken Diego Acosta-Alvear Tomás Aragón Carolina Arias Marc Blondel Ineke Braakman Jean-François Collet René Courcol Antoine Danchin Jean-François Deleuze Jean-Philippe Lavigne Sophie Lucas Thomas Michiels Edward R. B. Moore Jonathon Nixon-Abell Ramon Rossello-Mora Zheng-Li Shi Antonio G. Siccardi Roberto Sitia Daniel Tillett Kenneth N. Timmis Michel B. Toledano Peter van der Sluijs Elisa Vicenzi 《Environmental microbiology》2020,22(6):1997-2000
The current SARS-CoV-2 pandemic is wreaking havoc throughout the world and has rapidly become a global health emergency. A central question concerning COVID-19 is why some individuals become sick and others not. Many have pointed already at variation in risk factors between individuals. However, the variable outcome of SARS-CoV-2 infections may, at least in part, be due also to differences between the viral subspecies with which individuals are infected. A more pertinent question is how we are to overcome the current pandemic. A vaccine against SARS-CoV-2 would offer significant relief, although vaccine developers have warned that design, testing and production of vaccines may take a year if not longer. Vaccines are based on a handful of different designs (i), but the earliest vaccines were based on the live, attenuated virus. As has been the case for other viruses during earlier pandemics, SARS-CoV-2 will mutate and may naturally attenuate over time (ii). What makes the current pandemic unique is that, thanks to state-of-the-art nucleic acid sequencing technologies, we can follow in detail how SARS-CoV-2 evolves while it spreads. We argue that knowledge of naturally emerging attenuated SARS-CoV-2 variants across the globe should be of key interest in our fight against the pandemic. 相似文献
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46.
Jose Luis Martinez-Sande Javier Garcia-Seara Laila Gonzalez-Melchor Moises Rodriguez-Mañero Aurora Baluja Xesus Alberte Fernandez-Lopez Jose Ramon Gonzalez Juanatey 《Indian pacing and electrophysiology journal》2021,21(2):89-94
PurposeDespite the developments in conventional transvenous pacemakers (VVI-PM), the procedure is still associated with significant complications. Although there are no prospective clinical trials that compared VVI-PM with transcatheter pacemaker systems (TPS).MethodsThis is a prospective, observational, single-center study that included all patients with an indication for a single-chamber pacemaker implant within a 4-year period. All clinical, ECG and echocardiographic characteristics at implant, electrical parameters, associated complications and mortality were analyzed. A Cox survival model and a Bayesian cohort analysis were performed for differences in complication rates between groups.ResultsThere were 443 patients included (198 TPS and 245 VVI-PM). The mean age was 81.5 years (TPS group, 79.2 ± 6.6 years; VVI-PM group, 83.5 ± 8.9 years). There was a male predominance in TPS group (123, 62.1% vs. 67, 27.3%; p < 0.001). The presence of systolic dysfunction and renal insufficiency were more frequent in VVI-PM group than in TPS patients. Mean follow-up was 22.3 ± 15.9 months. In a multivariable paired data the TPS group presented fewer complications than VVI-PM group (HR = 0.39 [0.15–0.98], p-value 0.013), but major complications were not different (6, 3% vs 14, 5.6% respectively, p = 0.1761). There was no difference in the mortality rate between the groups. The TPS group had less risk than VVI-PM group to have a complication, with a 96% of probability.ConclusionsTPS patients had a lower overall complication rate than VVI-PM patients including matched-pair samples using a Bayesian analysis. These results confirm the safety profile of TPS in clinical practice. 相似文献
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48.
Mª Dolores Ramos-Barbero Tomeu Viver Ane Zabaleta Ece Senel María Gomariz Iñaki Antigüedad Fernando Santos Manuel Martínez-García Ramon Rosselló-Móra Josefa Antón 《Environmental microbiology》2021,23(7):3477-3498
Microbial communities in hypersaline underground waters derive from ancient organisms trapped within the evaporitic salt crystals and are part of the poorly known subterranean biosphere. Here, we characterized the viral and prokaryotic assemblages present in the hypersaline springs that dissolve Triassic-Keuper evaporite rocks and feed the Añana Salt Valley (Araba/Alava, Basque Country, Spain). Four underground water samples (around 23% total salinity) with different levels of exposure to the open air were analysed by means of microscopy and metagenomics. Cells and viruses in the spring water had lower concentrations than what are normally found in hypersaline environments and seemed to be mostly inactive. Upon exposure to the open air, there was an increase in activity of both cells and viruses as well as a selection of phylotypes. The underground water was inhabited by a rich community harbouring a diverse set of genes coding for retinal binding proteins. A total of 35 viral contigs from 15 to 104 kb, representing partial or total viral genomes, were assembled and their evolutionary changes through the spring system were followed by SNP analysis and metagenomic island tracking. Overall, both the viral and the prokaryotic assemblages changed quickly upon exposure to the open air conditions. 相似文献
49.
Sven Wagner Michael Eisenhut Ramon Eritja Franz Oberdorfer 《Nucleosides, nucleotides & nucleic acids》2013,32(7-9):1789-1792
Abstract An efficient procedure for the preparation of oligonucleotides carrying a mono-N-substituted azamacrocycle and its radiolabeled complex with Cu-64 and Tc-99m is reported. The new derivatives are of potential interest for Positron Emission Tomography and Single Photon Emission Tomography. 相似文献
50.
Anna Castro Carles Codony Ramon Eritja 《Nucleosides, nucleotides & nucleic acids》2013,32(12):2189-2197
Abstract A hybridoma against the nucleoside m6A has been obtained from mouse spleen. This hybridoma was named H65 and it secretes monoclonal antibodies anti-m6A. The competition assays showed that the monoclonal antibody was highly specific for m6A nucleoside. 相似文献