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51.
Photosynthetic reaction centers of Blastochloris viridis require two quanta of light to catalyse a two-step reduction of their secondary ubiquinone Q(B) to ubiquinol. We employed capacitive potentiometry to follow the voltage changes that were caused by the accompanying transmembrane proton displacements. At pH 7.5 and 20 degrees C, the Q(B)-related voltage generation after the first flash was contributed by a fast, temperature-independent component with a time constant of approximately 30 micros and a slower component of approximately 200 micros with activation energy (E(a)) of 50 kJ/mol. The kinetics after the second flash featured temperature-independent components of 5 micros and 200 micros followed by a component of 600 micros with E(a) approximately 60 kJ/mol. 相似文献
52.
Mathieu Berg Hanno Langen Jean-Pierre Claverys Bernard Martin 《Journal of bacteriology》2002,184(2):610-613
Competence for genetic transformation of Streptococcus pneumoniae is a transient physiological property inducible by a competence-stimulating peptide (CSP). A 68-kDa CSP-inactivating protein was previously obtained following lithium chloride (LiCl) extraction. By the same protocol, a CSP-inactivating protein was purified and identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry as an endopeptidase, PepO. Analysis of a pepO mutant provided no support for the hypothesis that PepO participates in competence regulation. To reconcile in vitro and in vivo data, we suggest that LiCl treatment results in the release of intracellular molecules, including PepO. 相似文献
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Ohne Zusammenfassung 相似文献
56.
Katrina Vanura Franz Rieder Marie-Theres Kastner Julia Biebl Michael Sandhofer Trang Le Robert Strassl Elisabeth Puchhammer-St?ckl Thomas Perkmann Christoph F. Steininger Kostas Stamatopoulos Wolfgang Graninger Ulrich J?ger Christoph Steininger 《PloS one》2013,8(10)
Chronic lymphocytic leukemia (CLL) is characterized by progressive hypogammaglobulinemia predisposing affected patients to a variety of infectious diseases but paradoxically not to cytomegalovirus (CMV) disease. Moreover, we found reactivity of a panel of CLL recombinant antibodies (CLL-rAbs) encoded by a germ-line allele with a single CMV protein, pUL32, despite differing antibody binding motifs. To put these findings into perspective, we studied prospectively relative frequency of viremia, kinetics of total and virus-specific IgG over time, and UL32 genetic variation in a cohort of therapy-naive patients (n=200). CMV-DNA was detected in 3% (6/200) of patients. The decay of total IgG was uniform (mean, 0.03; SD, 0.03) and correlated with that of IgG subclasses 1-4 in the paired samples available (n=64; p<0.001). Total CMV-specific IgG kinetics were more variable (mean, 0,02; SD, 0,06) and mean decay values differed significantly from those of total IgG (p=0.034). Boosts of CMV-specific antibody levels were observed in 49% (22/45) of CMV-seropositive patients. In contrast, VZV- and EBV-specific IgG levels decayed in parallel with total IgG levels (p=0.003 and p=0.001, respectively). VZV-specific IgG even became undetectable in 18% (9/50) of patients whereas CMV-specific ones remained detectable in all seropositive patients. The observed CMV-specific IgG kinetics were predicated upon the highly divergent kinetics of IgG specific for individual antigens - glycoprotein B-specific IgG were boosted in 51% and pUL32-specific IgG in 32% of patients. In conclusion, CLL patients have a preserved CMV-specific antibody response despite progressive decay of total IgG and IgG subclasses. CMV-specific IgG levels are frequently boosted in contrast to that of other herpesviruses indicative of a higher rate of CMV reactivation and antigen-presentation. In contrast to the reactivity of multiple different CLL-rAbs with pUL32, boosts of humoral immunity are triggered apparently by other CMV antigens than pUL32, like glycoprotein B. 相似文献
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Richard Biebl 《Protoplasma》1939,32(1):443-463
Ohne ZusammenfassungFür die Bereitstellung eines Arbeitsplatzes an der Staatlichen Biologischen Anstalt auf Helgoland und die freundliche Unterstützung, die ich dort erfahren habe, sage ich dem Direktor der Anstalt, Prof. Dr. Hagmeier sowie den Herren des Institutes meinen besten Dank.Herrn Univ.-Prof. Dr. V. Schiffner, Wien habe ich wiederum für die liebenswürdige Bestimmung einiger Versuchsalgen herzlich zu danken. 相似文献
59.
Ohne ZusammenfassungHerrn Professor Dr. Karl Höfler zu seinem 70. Geburtstag in Dankbarkeit gewidmet.This investigation was supported by the International Atomic Energy Agency. 相似文献
60.
Microbial production of 1,3-propanediol 总被引:79,自引:2,他引:77
H. Biebl K. Menzel A.-P. Zeng W.-D. Deckwer 《Applied microbiology and biotechnology》1999,52(3):289-297
1,3-Propanediol (1,3-PD) production by fermentation of glycerol was described in 1881 but little attention was paid to this
microbial route for over a century. Glycerol conversion to 1,3-PD can be carried out by Clostridia as well as Enterobacteriaceae.
The main intermediate of the oxidative pathway is pyruvate, the further utilization of which produces CO2, H2, acetate, butyrate, ethanol, butanol and 2,3-butanediol. In addition, lactate and succinate are generated. The yield of 1,3-PD
per glycerol is determined by the availability of NADH2, which is mainly affected by the product distribution (of the oxidative pathway) and depends first of all on the microorganism
used but also on the process conditions (type of fermentation, substrate excess, various inhibitions). In the past decade,
research to produce 1,3-PD microbially was considerably expanded as the diol can be used for various polycondensates. In particular,
polyesters with useful properties can be manufactured. A prerequisite for making a “green” polyester is a more cost-effective
production of 1,3-PD, which, in practical terms, can only be achieved by using an alternative substrate, such as glucose instead
of glycerol. Therefore, great efforts are now being made to combine the pathway from glucose to glycerol successfully with
the bacterial route from glycerol to 1,3-PD. Thus, 1,3-PD may become the first bulk chemical produced by a genetically engineered
microorganism.
Received: 12 January 1999 / Received revision: 9 March 1999 / Accepted: 14 March 1999 相似文献