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101.
We found that erythrocytes of zebrafish have cytoplasmic peroxidase activity. Blood in the zebrafish brain was visualized using a standard peroxidase staining method after formaldehyde fixation. The erythrocytes in the brain were heavily stained, but neurons and glias were not stained at all. This easy method enables the distribution of erythrocytes in the whole brain to be determined, and enables the actual number of erythrocytes in each area in the brain to be calculated. The paths of major, thick blood vessels in zebrafish brain are similar to those in higher vertebrates, however, the distribution of thin blood vessels is different. We also found that the erythrocytes were unevenly distributed in the brain. For example, the density of erythrocytes in the surface layer of the tectum was more than 30-fold higher than in the deeper granular layer. Very few erythrocytes were found in bundles of axons like cranial nerves and the medial longitudinal fascicle. In general, fewer erythrocytes were found in areas near the ventricle, whereas many more were found closer to the surface of the brain. The distribution of erythrocytes in the brains of sleeping, awake and actively moving fish were compared. In the brains of sleeping fish, most of the erythrocytes were present in large vessels. This was not observed in brains of awake or actively moving fish. We found that the blood supply to motor neurons in the ventral horn of the spinal cord increased during active movement compared to that in awake or sleeping fish. 相似文献
102.
Apoptosis is prevalent during development of the central nervous system (CNS), yet very little is known about the signals that specify an apoptotic cell fate. In this paper, we examine the role of Numb/Notch signaling in the development of the serotonin lineage of Drosophila and show that it is necessary for regulating apoptosis. Our results indicate that when Numb inhibits Notch signaling, cells undergo neuronal differentiation, whereas cells that maintain Notch signaling initiate apoptosis. The apoptosis inhibitor p35 can counteract Notch-mediated apoptosis and rescue cells within the serotonin lineage that normally undergo apoptosis. Furthermore, we observe tumor-like overproliferation of cells in the CNS when Notch signaling is reduced. These data suggest that the distribution of Numb during terminal mitotic divisions of the CNS can distinguish between a neuronal cell fate and programmed cell death. 相似文献
103.
Villalobos Virginia Suárez Jacqueline Estévez Jesús Novo Ernesto Bonilla Ernesto 《Neurochemical research》2001,26(10):1157-1161
In the present study the effects of chronic manganese (Mn) treatment on adenosine A2a receptor binding in mouse brain have been assessed. Male albino mice were divided in two groups: In the Mn-treated group, the animals were injected intraperitoneally (i.p.) with MnCl2 (5 mg/kg/day) five days per week during 9 weeks; in the control group, they were injected likewise with a saline solution. A significant decrease of the Kd without alteration of Bmax in the cerebellum and, an increase of the Kd and Bmax in hippocampus of mice treated with Mn were found. Also, an increase of Kd in frontal cortex was observed. The binding parameters in caudate nucleus, olfactory bulb and hypothalamus were not altered by Mn. A significant decrease in the adenosine concentration in caudate nucleus, olfactory bulb and hypothalamus, without significant changes in hippocampus, frontal cortex and cerebellum was also detected. These findings suggest that chronic administration of Mn could affect adenosine receptor function and turnover, depending on the brain region analyzed. 相似文献
104.
Medina-Leendertz S Valero N Chacín-Bonilla L Añez F Giraldoth D Arias J Espina G Díaz S Bonilla E 《Neurochemical research》2001,26(3):231-234
In mice infected with the Venezuelan equine encephalomyelitis (VEE) virus and exposed to high intensity light (2500 lux) with a 12 h light: 12 h dark photoperiod, a significant increase in the levels of melatonin in the olfactory bulb was observed. The significance of these findings deserves further studies to understand the mechanisms involved in this effect since the olfactory bulbs have been proposed as first portal for VEE virus entry into the CNS. The increase in melatonin content could represent one of the mechanisms of defense against the viral attack. 相似文献
105.
106.
Spatial and Temporal Deposition of Adhesive Extracellular Polysaccharide Capsule and Fimbriae by Hyphomonas Strain MHS-3 下载免费PDF全文
Hyphomonas strain MHS-3, a member of a genus of primary colonizers of surfaces immersed in marine water, synthesizes two structures that mediate adhesion to solid substrata, namely, capsular exopolysaccharide and fimbriae. Specific stains, gold-labelled lectins, and monoclonal antibodies, along with transmission electron microscopy of synchronized populations, revealed that both structures are polarly and temporally expressed. The timed synthesis and placement of the fimbriae and capsule correlated with the timing and locus of MHS-3 adhesion. 相似文献
107.
108.
Nitrogen distribution and leaf area indices in relation to photosynthetic nitrogen use efficiency in savanna grasses 总被引:3,自引:0,他引:3
Leaf photosynthetic characteristics, distribution patterns of nitrogen content per unit leaf area (nL) and leaf area production per unit nLwere measured in natural stands of a C4 grass (Hyparrhenia rufa) from the seasonal savannas and of a C4grass (Paspalum fasciculatum) and two C3grasses (Leersia hexandra and Hymenachne amplexicaulis) from the flooded savannas in central Venezuela. Daily rates of canopy photosynthesis (PcD) as well as the optimal leaf area production per unit nLat which PcDfor a given total amount of nitrogen in the canopy (i.e., canopy-PNUE) is maximized were also calculated. The C3and C4species from the flooded savannas had similar light saturated rates of photosynthesis per unit nL(i.e. leaf-PNUE) and similar canopy-PNUEs which was in strong contrast with previous studies. Especially H. rufa but also L. hexandra and H. amplexicaulis had leaf- and canopy-PNUEs which were considerably higher than the values calculated for most other species with the same photosynthetic pathway (i.e., C3or C4). In contrast to previous studies, differences in the light gradient in the canopy between stands only partially explained differences in N distribution. Measured leaf area indices were greater and the average nL values were consequently smaller than the calculated optima. There was, however, a very strong linear correlation between the optimal and actual average nLindicating that even though the model overestimated average nL, it did predict the differences in leaf area production per unit nitrogen – the inverse average nL– very well. This result strongly indicates that leaf area production per unit of leaf nitrogen increases with leaf-PNUE and decreases with the extinction coefficient for light. Grass species from seasonal savannas have extremely high leaf-PNUEs and thus optimally produce large amounts of leaf area per unit nL. This helps explain how stands of these species may have high leaf area indices and achieve high photosynthetic productivity despite the very low nutrient availability at which they grow. 相似文献
109.
Paul E. Rolan Gilmore O’Neill Eve Versage Jitesh Rana Yongqiang Tang Gerald Galluppi Ernesto Aycardi 《PloS one》2015,10(5)
ObjectiveTo evaluate the safety, tolerability, and pharmacokinetics of single doses of BG00010 (neublastin, artemin, enovin) in subjects with unilateral sciatica.MethodsThis was a single-center, blinded, placebo-controlled, randomized Phase 1 sequential-cohort, dose-escalation study (ClinicalTrials.gov identifier ; funded by Biogen Idec). Adults with unilateral sciatica were enrolled at The Royal Adelaide Hospital, Australia. Four subjects were assigned to each of eleven cohorts (intravenous BG00010 0.3, 1, 3, 10, 25, 50, 100, 200, 400, or 800 μg/kg, or subcutaneous BG00010 50 μg/kg) and were randomized 3:1 to receive a single dose of BG00010 or placebo. The primary safety and tolerability assessments were: adverse events; clinical laboratory parameters and vital signs; pain as measured by a Likert rating scale; intra-epidermal nerve fiber density; and longitudinal assessment of quantitative sensory test parameters. Blood, serum, and plasma samples were collected for pharmacokinetic and pharmacodynamic assessments. Subjects were blinded to treatment assignment throughout the study. The investigator was blinded to treatment assignment until the Data Safety Review Committee review of unblinded data, which occurred after day 28.ResultsBeyond the planned enrollment of 44 subjects, four additional subjects were enrolled into to the intravenous BG00010 200 μg/kg cohort after one original subject experienced mild generalized pruritus. Therefore, a total of 48 subjects were enrolled between August 2009 and December 2011; all were included in the safety analyses. BG00010 was generally well tolerated: in primary analyses, the most common treatment-emergent adverse events were changes in temperature perception, pruritus, rash, or headache; no trends were observed in clinical laboratory parameters, vital signs, intra-epidermal nerve fiber density, or quantitative sensory testing. BG00010 was not associated with any clear, dose-dependent trends in Likert pain scores. BG00010 was rapidly distributed, with a prolonged terminal elimination phase.ConclusionsThese data support the development of BG00010 for the treatment of neuropathic pain. NCT00961766
Trial Registration
ClinicalTrials.gov NCT00961766相似文献110.
Ernesto Maddaloni Nader Lessan Alia Al Tikriti Raffaella Buzzetti Paolo Pozzilli Maha T. Barakat 《PloS one》2015,10(8)