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131.
Responses of acutely isolated neurons from the rostral nucleus of the
solitary tract (rNST) to GABA receptor agonists and antagonists were
investigated using whole-cell recording in current clamp mode. The isolated
neurons retain their morphology and can be divided into multipolar,
elongate and ovoid cell types. Most rNST neurons (97%), including all three
cell types, respond to GABA with membrane hyperpolarization and a reduction
in input resistance. The GABA(A) receptor agonist muscimol reduces neuronal
input resistance in a concentration-dependent manner, whereas the GABA(B)
receptor agonist baclofen had no effect on any of the neurons tested. The
GABA and muscimol reversal potentials were both found to be -75 mV Both the
GABA competitive antagonist picrotoxin and the GABA(A) receptor antagonist
bicuculline block the effect of GABA in a concentration-dependent manner.
These results suggest that GABA activates all neurons in the rNST and that
inhibitory synaptic activity is important in brainstem processing of
gustatory and somatosensory information.
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132.
Sarah B. Rosche ChristopheR E. Moorman Krishna Pacifici Jeffrey G. Jones Christopher S. DePerno 《The Journal of wildlife management》2019,83(5):1226-1236
Despite the acknowledged importance of prescribed fire in creating northern bobwhite (Colinus virginianus) breeding cover, little research has investigated bobwhite breeding season habitat selection relative to time since fire. In 2016 and 2017, we monitored radio-tagged bobwhite on a 17,000-ha portion of a military installation managed with frequent (every ~3 years) prescribed fires, applied during the growing and dormant seasons. We monitored bobwhite to determine which vegetation characteristics associated with prescribed burning were important to bobwhite breeding season habitat selection at the microsite (i.e., telemetry location compared to nearby random location) and the macrosite scale (i.e., the burn-unit containing the location compared to study area availability). During 2 breeding seasons, we collected 2,315 bobwhite locations and compared percent cover of vegetation, days since burn, basal area, and distance to key landscape features (e.g., stream, wildlife opening) at a subset of microsite locations (301 locations during 2016 and 890 locations during 2017) to paired random locations. At the microsite scale, bobwhite selected lower basal area of hardwoods, greater woody understory cover, greater other (not wiregrass [Aristida stricta]) grass cover, and greater forb cover than at random points. At the macrosite scale, bobwhite selected units with <4.6 m2/ha basal area (combined hardwoods and pines) in 2016 and units with <9.2 m2/ha basal area in 2017. At the macrosite scale, bobwhite selected for areas burned in the dormant season of the same year, avoided areas burned in the growing season of the same year, and used other times since last burn categories proportionate to their availability. The selection for a low basal area at both scales indicates prescribed fire effects would be limited by shading from dense overstory, and the shrubs, grasses, and forbs that provide essential cover for bobwhite during the breeding season will not develop. In lower productivity soil regions similar to our study area, we advise that thinning operations set target basal areas below 10 m2/ha to create and maintain breeding season habitat for northern bobwhite. © 2019 The Wildlife Society 相似文献
133.
Replacement of receptor cells in the hamster vomeronasal epithelium after nerve transection 总被引:1,自引:1,他引:0
Chemoreceptor cells in the vomeronasal and olfactory epithelium are
replaced following experimentally induced degeneration. This study analyzes
quantitatively the time course and degree of vomeronasal receptor cell
replacement. Unilateral transection of the vomeronasal nerves in adult
hamster was used to induce a retrograde degeneration of receptor cells in
the vomeronasal organ. Histological measurement of both number of receptor
cells and epithelial thickness were made for recovery times from 0 to 60
days. After nerve transection, there was a gradual degeneration of receptor
cells, the number decreasing to 50% of control by day 2 and 16% by day 6.
During days 7-15 maximum receptor cell replacement was observed. Cell
number increased rapidly and reached a peak on day 15. At recovery times of
40-60 days, cell number returned to the control level. Epithelial
thickness, however, decreased to 60-70% during the degeneration period
(days 4-6) and did not return to control levels. After 40-60 days
epithelial thickness remained at 70% of control. These results demonstrate
that vomeronasal receptor cells are replaced following degeneration, but
epithelial thickness does not return to control levels. These findings
suggest that the number of replacement cells is not limited by the reduced
thickness of the epithelium, and that recovery mechanisms may function to
restore an optimum number of receptor cells.
相似文献
134.
The mutation G1691A (R506Q) in the human factor V gene is associated with the resistance to activated protein C (APC) that represents a major risk of development of venous thrombosis. A population study of 180 unrelated individuals from south Germany was performed. Examination of the allelic frequencies revealed a high prevalence of this disease-related mutation (Q506, FV Leiden). The heterozygosity rate was 7.8% with a confidence interval between 4% and 11%. 相似文献
135.
136.
Nazrat M. Mirza Kathleen Kadow Matilde Palmer Heidi Solano Claire Rosche Jack A. Yanovski 《Obesity (Silver Spring, Md.)》2004,12(8):1298-1310
Objective: National surveys have pointed to a particularly high risk of pediatric overweight among U.S. Hispanics. However, the data have been primarily from the Mexican‐American community. We studied the prevalence of overweight and clinical comorbidities in children and youth of predominantly El Salvadoran ancestry. Research Methods and Procedures: A sample of 309 Hispanic youth, 6–18 years was surveyed from two inner city Washington, DC, clinics. BMI; triceps skinfold (TSF) and subscapular skinfold thickness (SSSF); bioelectrical impedance analysis (BIA); and blood pressure measures were obtained, along with information regarding physical activity, sedentary behavior, dietary history, family, and personal medical history. Results: Thirty‐eight percent were overweight (BMI ≥ 95th percentile) and 22% at risk for overweight (BMI 85–94th percentile). Thirty‐four percent had TSF ≥ 90th percentile and 29% had SSSF ≥ 90th percentile. Fifty‐one percent of males and 70% of females had body fat > 30%. Compared to their nonoverweight counterparts, overweight youth had significantly higher systolic blood pressure (111.4 ± 1.3 vs. 104.5 ± 0.9 mm Hg, p < 0.0001). Among children younger than 11 years, overweight was associated with onset of adrenarche (23% vs. 10%, p = 0.01). Participation in one or more sports teams was negatively correlated with overweight) p = 0.04). Discussion: The prevalence of overweight and at risk for overweight in this sample was twice the national average for U.S. children and 1.7 times greater than that of Mexican‐American children in national surveys. Overweight was associated with advanced pubertal development, high body fat, elevated blood pressure, and decreased sports participation. 相似文献
137.
138.
Single-stranded DNA-binding protein enhances the stability of CTG triplet repeats in Escherichia coli. 总被引:3,自引:1,他引:2 下载免费PDF全文
W A Rosche A Jaworski S Kang S F Kramer J E Larson D P Geidroc R D Wells R R Sinden 《Journal of bacteriology》1996,178(16):5042-5044
The stability of CTG triplet repeats was analyzed in Escherichia coli to identify processes responsible for their genetic instability. Using a biochemical assay for stability, we show that the absence of single-stranded-DNA-binding protein leads to an increase in the frequency of large deletions within the triplet repeats. 相似文献