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101.
102.
RNA thermometers are thermosensors that regulate gene expression by temperature-induced changes in RNA conformation. Naturally occurring RNA thermometers exhibit complex secondary structures which are believed to undergo a series of gradual structural changes in response to temperature shifts. Here, we report the de novo design of considerably simpler RNA thermometers that provide useful RNA-only tools to regulate bacterial gene expression by a shift in the growth temperature. We show that a single small stem-loop structure containing the ribosome binding site is sufficient to construct synthetic RNA thermometers that work efficiently at physiological temperatures. Our data suggest that the thermometers function by a simple melting mechanism and thus provide minimum size on/off switches to experimentally induce or repress gene expression by temperature. 相似文献
103.
Juliane Feurle Eric Espinosa Susanne Eckstein Frédéric Pont Volker Kunzmann Jean-Jacques Fournié Markus Herderich Martin Wilhelm 《The Journal of biological chemistry》2002,277(1):148-154
Human Vgamma9delta2 T lymphocytes are suggested to play an important role in the immune response to various microbial pathogens. In contrast to alphabeta T cells, gammadelta T lymphocytes recognize small, non-protein, phosphate-bearing antigens (phosphoantigens) in a major histocompatibility complex-independent manner. Four different phosphoantigens termed TUBag1 to TUBag4 with a common 3-formyl-1-butyl-pyrophosphate moiety and isopentenyl-pyrophosphate have been isolated and identified from mycobacteria. However, natural occurring gammadelta T cell ligands from other bacterial species were not characterized so far. Here, we describe the structural identification of the two compounds responsible for the gammadelta T cell-stimulating capacity of Escherichia coli as similar to the mycobacterial phosphoantigens 3-formyl-1-butyl-pyrophosphate and its M(r) 275 homologue TUBag2. In addition, E. coli phosphoantigens exert bioactivities on gammadelta T cells with similar potencies to the mycobacterial phosphoantigens at 5-15 nm concentration. Furthermore, our results clearly prove that the deoxyxylulose 5-phophate pathway (also referred to as Rohmer metabolic route of isoprenoid biosynthesis) is essential for the biosynthesis of the phosphoantigens in E. coli. Because this pathway is absent from human cells, it proves an ideal target for focusing efficiently the antimicrobial selectivity of human gammadelta T lymphocytes. 相似文献
104.
Effect of different carbon sources on the enhanced biological phosphorus removal in a sequencing batch reactor 总被引:1,自引:0,他引:1
Hollender Juliane van der Krol Doris Kornberger Liane Gierden Edith Dott Wolfgang 《World journal of microbiology & biotechnology》2002,18(4):359-364
The effect of the different carbon sources acetate, acetate/glucose or glucose on the enhanced biological phosphorus removal
(EBPR) process was studied by experiments under alternating anaerobic–aerobic conditions in one sequencing batch reactor for
each carbon source. The glucose was consumed completely within the first 30 min of the anaerobic phase whereas acetate degradation
was slow and incomplete. Phosphate was released independently of the carbon source during the whole anaerobic phase. The highest
phosphate release (27 mg P l−1) and polyhydroxyalkanoate (PHA) storage (20 mg C g−1 dry matter (DM)) during the anaerobic phase as well as the highest polyphosphate (poly-P) (8 mg P g−1 DM) and glycogen storage (17 mg C g−1 DM) during the aerobic phase were observed with acetate. In contrast to other investigations, glycogen storage did not increase
with glucose as substrate but was significantly smaller than with acetate. The PHA composition was also influenced strongly
by the carbon source. The polyhydroxyvalerate (PHV) portion of the PHA was maximal 17% for acetate and 82% for glucose. Due
to the strong influence of the carbon source on the PHA concentration and composition, PHA storage seems to regulate mainly
the phosphate release and uptake.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
105.
Domestic dogs are skillful at using the human pointing gesture. In this study we investigated whether dogs take contextual information into account when following pointing gestures, specifically, whether they follow human pointing gestures more readily in the context in which food has been found previously. Also varied was the human''s tone of voice as either imperative or informative. Dogs were more sustained in their searching behavior in the ‘context’ condition as opposed to the ‘no context’ condition, suggesting that they do not simply follow a pointing gesture blindly but use previously acquired contextual information to inform their interpretation of that pointing gesture.Dogs also showed more sustained searching behavior when there was pointing than when there was not, suggesting that they expect to find a referent when they see a human point. Finally, dogs searched more in high-pitched informative trials as opposed to the low-pitched imperative trials, whereas in the latter dogs seemed more inclined to respond by sitting. These findings suggest that a dog''s response to a pointing gesture is flexible and depends on the context as well as the human''s tone of voice. 相似文献
106.
Simon Trapp Ali A. Aghdassi Juliane Glaubitz Matthias Sendler Frank Ulrich Weiss Jens Peter Kühn Marie-Luise Kromrey Ujjwal M. Mahajan Petra Pallagi Zoltán Rakonczay Jr Viktória Venglovecz Markus M. Lerch Peter Hegyi Julia Mayerle 《Journal of cellular and molecular medicine》2021,25(10):4658-4670
Mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) are an established risk factor for cystic fibrosis (CF) and chronic pancreatitis. Whereas patients with CF usually develop complete exocrine pancreatic insufficiency, pancreatitis patients with CFTR mutations have mostly preserved exocrine pancreatic function. We therefore used a strain of transgenic mice with significant residual CFTR function (CFTRtm1HGU) to induce pancreatitis experimentally by serial caerulein injections. Protease activation and necrosis were investigated in isolated acini, disease severity over 24h, pancreatic function by MRI, isolated duct stimulation and faecal chymotrypsin, and leucocyte function by ex vivo lipopolysaccharide (LPS) stimulation. Pancreatic and lung injury were more severe in CFTRtm1HGU but intrapancreatic trypsin and serum enzyme activities higher than in wild-type controls only at 8h, a time interval previously attributed to leucocyte infiltration. CCK-induced trypsin activation and necrosis in acini from CFTRtm1HGU did not differ from controls. Fluid and bicarbonate secretion were greatly impaired, whereas faecal chymotrypsin remained unchanged. LPS stimulation of splenocytes from CFTRtm1HGU resulted in increased INF-γ and IL-6, but decreased IL-10 secretion. CFTR mutations that preserve residual pancreatic function significantly increase the severity of experimental pancreatitis—mostly via impairing duct cell function and a shift towards a pro-inflammatory phenotype, not by rendering acinar cells more susceptible to pathological stimuli. 相似文献
107.
Anže Žerdoner Čalasan Juliane Kretschmann Marc Gottschling 《Organisms Diversity & Evolution》2018,18(1):29-38
Tertiary endosymbiosis is proven through dinophytes, some of which (i.e. Kryptoperidiniaceae) have engulfed diatom algae containing a secondary plastid. Chloroplasts are usually inherited together permanently with the host cell, leading to co-phylogeny. We compiled a diatom sequence data matrix of two nuclear and two chloroplast loci. Almost all endosymbionts of Kryptoperidiniaceae found their closest relatives in free-living diatoms and not in other harboured algae, rejecting co-phylogeny and indicating that resident diatoms were taken up by dinophytes multiple times independently. Almost intact ultrastructure and insignificant genome reduction are supportive for young, if not recent events of diatom capture. With their selective specificity on the one hand and extraordinary degree of endosymbiotic flexibility on the other hand, dinophytes hosting diatoms share more traits with lichens or facultatively phototrophic ciliates than with green algae and land plants. Time estimates indicate the dinophyte lineages as consistently older than the hosted diatom lineages, thus also favouring a repeated uptake of endosymbionts. The complex ecological role of dinophytes employing a variety of organismic interactions may explain their high potential and plasticity in acquiring a great diversity of plastids. 相似文献
108.
Irene Pila-Castellanos Diana Molino Joe McKellar Laetitia Lines Juliane Da Graca Marine Tauziet Laurent Chanteloup Ivan Mikaelian Laurne Meyniel-Schicklin Patrice Codogno Jacky Vonderscher Cdric Delevoye Olivier Moncorg Eric Meldrum Caroline Goujon Etienne Morel Benoit de Chassey 《PLoS pathogens》2021,17(2)
Influenza virus infections are major public health threats due to their high rates of morbidity and mortality. Upon influenza virus entry, host cells experience modifications of endomembranes, including those used for virus trafficking and replication. Here we report that influenza virus infection modifies mitochondrial morphodynamics by promoting mitochondria elongation and altering endoplasmic reticulum-mitochondria tethering in host cells. Expression of the viral RNA recapitulates these modifications inside cells. Virus induced mitochondria hyper-elongation was promoted by fission associated protein DRP1 relocalization to the cytosol, enhancing a pro-fusion status. We show that altering mitochondrial hyper-fusion with Mito-C, a novel pro-fission compound, not only restores mitochondrial morphodynamics and endoplasmic reticulum-mitochondria contact sites but also dramatically reduces influenza replication. Finally, we demonstrate that the observed Mito-C antiviral property is directly connected with the innate immunity signaling RIG-I complex at mitochondria. Our data highlight the importance of a functional interchange between mitochondrial morphodynamics and innate immunity machineries in the context of influenza viral infection. 相似文献
109.
110.