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41.
The vav proto-oncogene product (Vav) is expressed exclusively in hematopoietic cells and is reported to have guanine nucleotide exchange activity. Here we report that granulocyte-macrophage colonystimulating factor, interleukin-3, and erythropoietin induce tyrosine phosphorylation of Vav in a human leukemia cell line UT-7. Tyrosine phosphorylation of Vav is rapid and transient; it occurs within 1 min of the stimulation and at physiological concentrations of the factors. Furthermore, we show that Vav is constitutively associated with the adapter molecule Grb2/Ash in UT-7. These data suggest that tryosine kinases, the adapter Grb2/Ash, and the guanine nucleotide exchange factor Vav are members of a signaling pathway leading to Ras activation in hematopoietic cells.  相似文献   
42.
目的 检测死于50年前的鼠疫病人尸骨及尸骨周围土壤是否存在鼠疫菌。方法 利用鼠疫细菌学和血清学方法对尸骨和土壤进行检验。结果 尸骨及土壤中没有分离到鼠疫菌。结论 在尸体腐烂过程中其条件不利于鼠疫菌存活,加之50~60年风干的环境亦可导致鼠疫菌的死亡。  相似文献   
43.
Widespread osteoporosis testing and diagnosis are currently limited due to the high capital cost and reduced portability of many existing bone densitometry techniques. In this study we evaluated an inexpensive, low radiation, X-ray-based technique for assessing bone density of the middle phalanx. The technique, termed computed digital absorptiometry (CDA), is similar to radiographic absorptiometry (RA), using a single-energy X-ray source, an aluminum alloy step-wedge, and a charge-coupled device (CCD) detector system to automatically compute bone mineral content (BMC, g) and bone mineral density (BMD, g/cm2) in the middle phalanx of the third finger. The potential advantage of CDA over current RA techniques is that by using a filmless detector system, no off-site processing of radiographs is required and bone density results are obtained immediately after the test. Using human cadaveric specimens we determined the accuracy and short-term precision of CDA as well as its correlation with other hand and forearm bone densitometry methods. We obtained 26 cadaveric forearms (50% female, mean age 78 years, range 52–96 years). BMC and BMD of the middle phalanx of the third finger were determined using CDA and using RA. We assessed forearm BMC and BMD using single-energy and dual-energy X-ray absorptiometry (SXA and DXA). Precision of CDA was assessed by measuring ten of the specimens five times each with repositioning between measurements. Finally, the middle phalanx was dissected and incinerated to determine ash weight. BMC estimates from CDA and from RA were strongly correlated with ash weight (r = 0.89, p < 0.001 and r = 0.93, p < 0.001, respectively). The mean coefficients of variation using CDA were 1.36% and 0.70% for phalanx BMC and BMD, respectively. BMC and BMD measured by CDA were strongly correlated with hand and forearm bone mineral measurements performed by SXA, DXA and TA (r = 0.74–0.91). These results indicate that CDA accurately and precisely predicts BMC of the middle phalanx. Thus, with further clinical verification, this technique may prove to be a useful tool for the wide-spread testing and assessment of osteoporotic fracture risk.  相似文献   
44.
In this study, cortical bone tissue from children was investigated. It is extremely difficult to obtain human child tissue. Therefore, the only possibility was to use bone tissue, free from any lesion, collected from young bone cancer patients.The compressive mechanical behaviour of child bone tissue was compared to the behaviour of adult tissue. Moreover, two hypotheses were tested: 1) that the mechanical behaviour of both groups is correlated to ash density; 2) that yield strain is an invariant.Small parts of the diaphysis of femora or tibiae from 12 children (4–15 years) and 12 adults (22–61 years) were collected. Cylindrical specimens were extracted from the cortical wall along the longitudinal axis of the diaphysis. A total of 107 specimens underwent compressive testing (strain rate: 0.1 s− 1). Only the specimens showing a regular load–displacement curve (94) were considered valid and thereafter reduced to ash.It was found that the child bone tissue had significant lower compressive Young's modulus (− 34%), yield stress (− 38%), ultimate stress (− 33%) and ash density (− 17%) than the adult tissue. Conversely, higher compressive ultimate strain was found in the child group (+ 24%). Despite specimens extracted from both children and adults, ash density largely described the variation in tissue strength and stiffness (R2 = in the range of 0.86–0.91). Furthermore, yield strain seemed to be roughly an invariant to subject age and tissue density.These results confirm that the mechanical properties of child cortical bone tissue are different from that of adult tissue. However, such differences are correlated to differences in tissue ash density. In fact, ash density was found to be a good predictor of strength and stiffness, also for cortical bone collected from children. Finally, the present findings support the hypothesis that compressive yield strain is an invariant.  相似文献   
45.
超声波洁治后喷砂抛光处理的临床效果研究   总被引:1,自引:2,他引:1  
曹军 《中国美容医学》2006,15(11):1303-1304
目的:观察超声波洁牙后使用喷砂抛光对软垢指数(DI)、菌斑指数(PI)和龈沟出血指数(SBI)的影响。方法:临床随机选择40例无牙缺失的牙周病患者进行超声波洁治,洁治后随机对同一病例左侧或右侧牙齿进行喷砂抛光,观察DI、PI和SBI的变化,对超声波洁治后使用喷砂抛光的临床效果进行评价。结果:超声波洁牙后使用喷砂抛光处理可以明显减少患者的DI和PI,随着时间的推移,未喷砂抛光侧的DI和PI增加更快;而SBI在治疗后逐步降低,效果可持续半年。结论:超声波洁治后使用喷砂抛光能提高牙面的清洁度、光滑度,不利于软垢、菌斑的再附着,促进牙周的健康。  相似文献   
46.
PurposeTo evaluate dislodgement of tunneled dialysis catheters (TDCs) in de novo (DN) placement with ultrasound versus over-the-wire exchange (OTWE).Materials and MethodsData were collected retrospectively on all TDC placements at this institution from 2001 to 2019 and were excluded if no removal date was recorded or if dwell time was more than 365 days. Information on TDC brand, placement, insertion/removal, and removal reason were collected. Multiple logistic regression evaluated factors associated with TDC dislodgement. DN placement and OTWE were compared for rate of dislodgement (generalized estimating equations method) and TDC dwell time (survival analysis).ResultsIn total, 5328 TDCs were included with 66% (3522) placed DN and 32% (1727) via OTWE. Mean dwell time was 65 ± 72 days, and dislodgement occurred in 4% (224). TDC dislodgement rates in the DN and OTWE groups were 0.48 and 0.93 per 1000 catheter days, respectively. Brand (Ash Split vs. VectorFlow), placement technique (OTWE vs. DN), laterality (left vs. right), and site (left vs. right internal jugular vein) were significant predictors of dislodgement. OTWE placement exhibited 1.7 times the odds of dislodgement (95% confidence interval, 1.2–2.6; P = .004) compared to DN and had significantly higher probability of dislodgement across time (hazard ratio = 2.0; P < .001) compared to DN. Dislodgement rates for OTWE vs. DN were 8% vs. 3% (3 months), 13% vs. 6% (6 months), and 38% vs. 17% (1 year).ConclusionsTDC spontaneous dislodgement rates were significantly and consistently higher after OTWE compared to DN placement. These data support more careful attention to catheter fixation after OTWE placement.  相似文献   
47.
Recreational open fires are an important and preventable cause of burn. In contrast to adults, who often sustain flame burns, children are at higher risk of thermal contact burns caused by hot embers many hours after the fire was first lit. Cases of thermal contact injury in children due to recreational fires were reviewed and the potential of a small charcoal fire to cause burns over a prolonged period was tested.Between 1993 and 2007, 67 children were admitted for treatment, with a median age of 1.6 years. Total burn surface area ranged from 0.5% to 19.5% (median 4%) with burns most commonly affecting the hands and feet. The average length of stay was 7 days and a total of 81 surgical procedures were carried out. Injury was most commonly sustained after falling into (40%), or accidentally crawling or walking on (30%), the remnants of an unextinguished fire. Small charcoal fires retain sufficient heat to cause injury at least 16 h after lighting. Strategies for prevention of these injuries are outlined.  相似文献   
48.
目的:确定2010年版《中华人民共和国药典》(1部)中灰分测定法的部分操作参数,细化操作程序。方法:分别应用2010年版《中华人民共和国药典》(1部)收载方法和改进后方法对所选样品进行总灰分、酸不溶性灰分的检查。结果:两种方法测定结果无显著性差异。结论:改进后方法更加规范,且省时节能。  相似文献   
49.
目的比较不同产地麻黄饮片质量,制定麻黄饮片质量的参考标准.方法采用 HPLC法测定各饮片的麻黄碱和伪麻黄碱含量,依照<中国药典> 2000年版一部的方法测定各饮片的浸出物、灰分、水分、杂质及灰屑等;并采用经验法进行加速稳定性试验.结果麻黄碱含量生品为 0.995 %~ 1.589 %,蜜炙品为 0.855 %~ 1.557 %;伪麻黄碱含量生品为 0.560 %~ 2.087 %,蜜炙品为 0.508 %~ 1.902 %;水溶性浸出物生品为 8.83 %~ 18.30 %,蜜炙品为 14.81 %~ 27.45 %;醇溶性浸出物生品为 7.74 %~ 18.83 %,蜜炙品为 14.15 %~ 27.34 %;总灰分生品为 6.49 %~ 10.29 %,蜜炙品为 6.34 %~ 10.24 %;酸不溶灰分生品为 0.19 %~ 0.42 %,蜜炙品为 0.18 %~ 0.42 %;平均含水量生品为 8.10 %( s=0.3961),蜜炙品为 4.02 %( s=0.4674);平均所含杂质及灰屑量生品为 2.02 %( s=0.1954),蜜炙品为 2.01 %( s=0.2209).结论 该研究为建立完整、科学的麻黄饮片质量标准提供了参考依据.  相似文献   
50.
王启华 《中外医疗》2016,(22):92-94
目的:对秦皮浴联合窄谱中波紫外线治疗寻常型银屑病疗效及安全性的评价。方法方便选择从2014年5月—2015年5月入住该院接受治疗的66例寻常型银屑病患者作为研究对象,随机分成实验组和常规组,每组33例。其中常规组患者采用窄谱中波紫外线进行治疗,实验组患者采用秦皮浴联合窄谱中波紫外线进行治疗。对两组患者的临床疗效及安全性进行对比和评价。结果治疗后与常规组的有效率(63.64%)相比,实验组治疗后的有效率(93.94%)显著偏高,且差异有统计学意义,P<0.05;与常规组的不良反应发生率(21.21%)相比,实验组的不良反应发生率(3.03%)明显偏低,且差异有统计学意义,P<0.05。结论秦皮浴联合窄谱中波紫外线治疗寻常型银屑病疗效较好,安全性亦较高。  相似文献   
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