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41.
ets-2 is a target for an akt (Protein kinase B)/jun N-terminal kinase signaling pathway in macrophages of motheaten-viable mutant mice 总被引:3,自引:0,他引:3 下载免费PDF全文
Smith JL Schaffner AE Hofmeister JK Hartman M Wei G Forsthoefel D Hume DA Ostrowski MC 《Molecular and cellular biology》2000,20(21):8026-8034
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Mammalian and plant purple acid phosphatases have similar active site structures despite low sequence identity (<20%). Although no bacterial enzyme has been purified, a sequence database search revealed that genes that could encode potential purple acid phosphatases may be restricted to a small number of organisms (i.e. myco- and cyanobacteria). Analysis of their deduced amino acid sequences and predicted secondary structures indicates that the cyanobacterial enzyme is similar to both the mammalian and the recently discovered low-molecular-weight plant purple acid phosphatases, while the mycobacterial enzyme is homologous to the fungal and high-molecular-weight plant purple acid phosphatases. Homology models indicate that both bacterial proteins appear to be similar to mammalian purple acid phosphatases in the immediate vicinity of the active site. It is likely that these enzymes act as Fenton-type catalysts in order to prevent damage caused by reactive oxygen species generated by invaded host cells (M. tuberculosis) or by the light-harvesting complex (Synechocystis sp.). 相似文献
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Neck afferents and muscle sympathetic activity in humans: implications for the vestibulosympathetic reflex 总被引:6,自引:0,他引:6
Ray, Chester A., and Keith M. Hume. Neck afferents andmuscle sympathetic activity in humans: implications for the vestibulosympathetic reflex. J. Appl.Physiol. 84(2): 450-453, 1998.We have shownpreviously that head-down neck flexion (HDNF) in humans elicitsincreases in muscle sympathetic nerve activity (MSNA). The purpose ofthis study was to determine the effect of neck muscle afferents onMSNA. We studied this question by measuring MSNA before and after headrotation that would activate neck muscle afferents but not thevestibular system (i.e., no stimulation of the otolith organs orsemicircular canals). After a 3-min baseline period with the head inthe normal erect position, subjects rotated their head to the side(~90°) and maintained this position for 3 min. Head rotation wasperformed by the subjects in both the prone(n = 5) and sitting(n = 6) positions. Head rotation did not elicit changes in MSNA. Average MSNA, expressed asburst frequency and total activity, was 13 ± 1 and 13 ± 1 bursts/min and 146 ± 34 and 132 ± 27 units/min during baselineand head rotation, respectively. There were no significant changes incalf blood flow (2.6 ± 0.3 to 2.5 ± 0.3 ml · 100 ml1 · min1;n = 8) and calf vascular resistance(39 ± 4 to 41 ± 4 units; n = 8). Heart rate (64 ± 3 to 66 ± 3 beats/min;P = 0.058) and mean arterial pressure(90 ± 3 to 93 ± 3; P < 0.05)increased slightly during head rotation. Additional neck flexionstudies were performed with subjects lying on their side(n = 5). MSNA, heart rate, and meanarterial pressure were unchanged during this maneuver, which also doesnot engage the vestibular system. HDNF was tested in 9 of the 13 subjects. MSNA was significantly increased by 79 ± 12% (P < 0.001) during HDNF. Thesefindings indicate that neck afferents activated by horizontal neckrotation or flexion in the absence of significant force development donot elicit changes in MSNA. These findings support the concept thatHDNF increases MSNA by the activation of the vestibular system. 相似文献
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Lee McMichael Daniel Edson Amanda McLaughlin David Mayer Steven Kopp Joanne Meers Hume Field 《PloS one》2015,10(5)
This paper establishes reference ranges for hematologic and plasma biochemistry values in wild Black flying-foxes (Pteropus alecto) captured in South East Queensland, Australia. Values were found to be consistent with those of other Pteropus species. Four hundred and forty-seven animals were sampled over 12 months and significant differences were found between age, sex, reproductive and body condition cohorts in the sample population. Mean values for each cohort fell within the determined normal adult reference range, with the exception of elevated levels of alkaline phosphatase in juvenile animals. Hematologic and biochemistry parameters of injured animals showed little or no deviation from the normal reference values for minor injuries, while two animals with more severe injury or abscessation showed leucocytosis, anaemia, thrombocytosis, hyperglobulinemia and hypoalbuminemia. 相似文献
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Christy E. Oliver Ross C. Beier Michael E. Hume Shane M. Horrocks Thomas A. Casey Joel S. Caton David J. Nisbet David J. Smith Nathan A. Krueger Robin C. Anderson 《Anaerobe》2010,16(2):106-113
Experiments were conducted to determine factors that affect sensitivity of Salmonella enterica serovar Typhimurium to sodium chlorate (5 mM). In our first experiment, cultures grown without chlorate grew more rapidly than those with chlorate. An extended lag before logarithmic growth was observed in anaerobic but not aerobic cultures containing chlorate. Chlorate inhibition of growth during aerobic culture began later than that observed in anaerobic cultures but persisted once inhibition was apparent. Conversely, anaerobic cultures appeared to adapt to chlorate after approximately 10 h of incubation, exhibiting rapid compensatory growth. In anaerobic chlorate-containing cultures, 20% of total viable counts were resistant to chlorate by 6 h and had propagated to 100% resistance (>109 CFU mL?1) by 24 h. In the aerobic chlorate-containing cultures, 12.9% of colonies had detectable resistance to chlorate by 6 h, but only 1% retained detectable resistance at 24 h, likely because these cultures had opportunity to respire on oxygen and were thus not enriched via the selective pressure of chlorate. In another study, treatment with shikimic acid (0.34 mM), molybdate (1 mM) or their combination had little effect on aerobic or anaerobic growth of Salmonella in the absence of added chlorate. As observed in our earlier study, chlorate resistance was not detected in any cultures without added chlorate. Chlorate resistant Salmonella were recovered at equivalent numbers regardless of treatment after 8 h of aerobic or anaerobic culture with added chlorate; however, by 24 h incubation chlorate sensitivity was completely restored to aerobic but not anaerobic cultures treated with shikimic acid or molybdate but not their combination. Results indicate that anaerobic adaptation of S. Typhimurium to sodium chlorate during pure culture is likely due to the selective propagation of low numbers of cells exhibiting spontaneous resistance to chlorate and this resistance is not reversible by molybdenum supplementation. 相似文献
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Bassam R. Ali Ian Nouvel Alistair N. Hume 《Biochemical and biophysical research communications》2010,397(1):34-41
Ras super-family small GTPases regulate diverse cellular processes such as vesicular transport and signal transduction. Critical to these activities is the ability of these proteins to target to specific intracellular membranes. To allow association with membranes Ras-related GTPases are post-translationally modified by covalent attachment of prenyl groups to conserved cysteine residues at or near their C-terminus. Here we used the HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase (HMGCR) inhibitor mevastatin to develop a ‘prenylation block-and-release’ assay that allows membrane targeting of prenylated proteins to be visualized in living cells. Using this assay we investigated the cytosol to membrane targeting of several small GTPases to compartments of the secretory and endocytic pathways. We found that all Rabs tested were targeted directly to the membrane on which they reside at steady-state and not via an intermediate location as reported for Ras and Rho proteins. However, we observed that the kinetics of cytosol to membrane targeting differed for each Rab tested. Comparison of the mevastatin sensitivity and kinetics of membrane targeting of Rab23, Rab23 prenylation motif mutants and H-Ras revealed that these parameters are strongly dependent upon the prenyl transferase with Rab geranylgeranyl transferase substrates exhibiting higher sensitivity and requiring greater time to recover from mevastatin inhibition than farnesyl transferase substrates. We propose that this assay is a useful tool to investigate the kinetics, biological functions and the mechanisms of membrane targeting of prenylated proteins. 相似文献
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