首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   55篇
  免费   13篇
  国内免费   4篇
  2023年   3篇
  2022年   3篇
  2021年   4篇
  2020年   5篇
  2019年   1篇
  2018年   1篇
  2017年   2篇
  2016年   1篇
  2015年   3篇
  2014年   6篇
  2013年   6篇
  2012年   1篇
  2011年   3篇
  2010年   3篇
  2009年   1篇
  2008年   1篇
  2007年   2篇
  2006年   2篇
  2005年   2篇
  2004年   1篇
  2003年   3篇
  2002年   1篇
  2001年   1篇
  2000年   2篇
  1999年   2篇
  1998年   2篇
  1996年   2篇
  1995年   3篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1990年   1篇
排序方式: 共有72条查询结果,搜索用时 31 毫秒
31.
目的:评价新生儿唇腭裂术前进行鼻-牙槽突-腭畸形矫治方法的疗效。方法:对28例单双侧唇腭裂新生儿进行术前鼻-牙槽突-腭畸形矫治治疗,在面部确定基点,利用数码相机拍射照片,通过image-Pro Plus5.1软件测量相关距离及角度,测量治疗前后的鼻小柱倾斜度、鼻小柱长度、鼻孔宽度和鼻孔高度。治疗前后取上颌石膏模型进行牙槽骨裂隙宽度的测量,比较矫治治疗前后腭部裂隙最大处及牙槽突裂隙的变化。结果:鼻小柱倾斜度平均减小27.11°,鼻孔宽度平均减小4.39 mm(单)或5.29 mm(双),鼻孔高度平均增加2.56 mm(单)或3.57 mm(双),牙槽突裂隙平均减少3.18 mm,腭部裂隙最大处平均减少5.77 mm。治疗前后的各项差异均有统计学意义(P0.05),鼻塌陷畸形程度也得到显著改善。结论:术前进行鼻-牙槽突-腭畸形矫治治疗可为唇腭裂患者手术治疗创造有利条件,提高其整复效果。  相似文献   
32.
目的:探讨胎儿肢体畸形超声特征及诊断价值。方法:采用连续顺序追踪法对66342例妊娠12-40周孕妇行胎儿四肢畸形筛查。将产前超声诊断结果与引产或产后结果进行对比分析。结果:发生肢体畸形271例,发生率为0.41%(271/66342),包括四肢短小5例,桡骨发育不全1例,缺肢畸形5例,足内翻17例,手掌畸形3例,指趾畸形222例及骨骼多发畸形18例。其中产前诊断胎儿肢体畸形49例;漏诊222例,包括:足内翻3例、指趾畸形218例、多发骨骼畸形1例。胎儿肢体畸形的出现率和产前检出率分别为:四肢短小1.84%(5/271)、100%(5/5);桡骨发育不全0.36%(1/271)、100%(1/1);缺肢畸形1.84%(5/271)、100%(5/5);足内翻6.27%(17/271)、82.35%(14/17);手掌畸形1.10%(3/271)、100%(3/3);指趾畸形81.91%(222/217)、1.8%(4/222);多发骨骼畸形6.64%(18/271)、94.44%(17/18)。结论:超声对胎儿手掌、脚掌部位以上畸形的检出率较高。指趾畸形出现率最高,但检出率最低。  相似文献   
33.
Abstract

Artificial neural networks (ANN's) recognize patterns relating input and output data in a manner analogous to the function of biological neurons. Here, we show that ANN's can predict rib deformity in scoliosis more accurately than regression analysis. ANN's and linear regression models were developed to predict rib rotation from several combinations of input spinal indices including Cobb angle, vertebral rotation, apex location and orientation of the plane of maximal curvature. ANN's averaged 60% correct predictions compared to 34% for regression analysis. This study provides evidence for the utility of artificial neural networks in scoliosis research. These data lend credence to the use of ANN's in future work on the prediction of scoliotic spinal deformity from torso surface data, which would permit assessment of scoliosis severity with minimal use of harmful X-rays.  相似文献   
34.
The recombinant limb is a model system that has proved fruitful for analyzing epithelial-mesenchymal interactions and understanding the functional properties of the components of the limb bud. Here we present an overview of some of the insights obtained through the use of this technique. Among these are the understanding that fore or hind limb identity is inherent to the limb bud mesoderm, that the apical ectodermal ridge (AER) is a permissive signaling center and that the limb bud ectoderm plays a central role in the control of dorsoventral polarity. Recombinant limb studies have also allowed the identification of the affected tissue component in several limb mutants. More recently this model has been applied to the study of regulation of gene expressions related to patterning. In this report we use recombinant limbs to analyze pattering of the Pax3 expressing limb muscle cell lineage in the early stages of limb development. In recombinant limbs made without the zone of polarizing activity (ZPA), myoblasts appear intermingled with other mesodermal cells at the beginning of the recombinant limb development. Rapidly thereafter, the muscle precursors segregate and organize around the central forming chondrogenic core of the recombinant. Although this segregation is reminiscent of that occurring during normal development, the myoblasts in the recombinant fail to proliferate appropriately and also fail to migrate distally. Consequently, the muscle pattern in the recombinant limb is defective indicating that normal patterning cues are absent. However, recombinant limbs polarized with a ZPA exhibited a larger mass of muscle cells and a more normal morphogenesis, supporting a role for this signaling center in limb muscle development. Finally, we have ruled out host somite contributions to recombinant limbs by grafting chick recombinant limbs to quail hosts. This initial report demonstrates the value of the recombinant limb model system for dissecting the environmental cues required for normal muscle limb patterning. Received: 31 August 1998 / Accepted: 29 September 1998  相似文献   
35.
摘要 目的:研究成人脊柱畸形患者矫正手术后力学性并发症的发生率以及影响其发生的危险因素。方法:纳入2016年6月到2020年6月在我院接受脊柱畸形矫正术的患者80例,术后对所有患者进行为期12个月的随访。根据患者术后随访期间是否出现力学性并发症分为力学并发症组和无力学并发症组,调查两组患者年龄、BMI、术中失血量、手术时间、合并神经损伤、术中截骨、性别、主弯角度、矫正率、手术史、入路以及疾病类型等病历资料,并通过单因素和多因素Logistic回归分析成人脊柱畸形矫正术后发生力学性并发症的独立危险因素。结果:80例脊柱畸形矫正术患者术后发生力学性并发症患者18例(22.50 %),分别为内固定失败4例、近端交界性失败5例、远端交界性失败4例以及术后冠状面失平衡5例。单因素分析结果表明,手术时间(OR=6.924,P=0.015)、年龄(OR=2.803,P=0.011)、矫正率(OR=3.215,P=0.032)、合并神经损伤(OR=1.629,P=0.021)、术中截骨术(OR=5.876,P=0.005)以及手术史(OR=1.692,P=0.043)与成人脊柱畸形矫正术后力学性并发症的发生有关。多因素Logistic回归分析结果表明,手术时间(OR=2.265,P=0.002)、年龄(OR=4.035,P<0.001)、合并神经损伤(OR=3.024,P=0.003)以及术中截骨术(OR=3.982,P<0.001)是成人脊柱畸形矫正术后发生力学性并发症的独立危险因素。结论:成年脊柱畸形患者矫正术后易发生力学性并发症,手术时间较长、年龄较大、合并神经损伤以及术中截骨术均会增加其发生风险。  相似文献   
36.
The use of conditioned medium from mesenchymal stem cells may be a feasible approach for regeneration of bone defects through secretion of various components of mesenchymal stem cells such as cytokines, chemokines, and growth factors. Mesenchymal stem cells secrete and accumulate multiple factors in conditioned medium under specific physiological conditions. In this study, we investigated whether the conditioned medium collected under hypoxic condition could effectively influence bone regeneration through enhanced migration and adhesion of endogenous mesenchymal stem cells. Cell migration and adhesion abilities were increased through overexpression of intercellular adhesion molecule-1 in hypoxic conditioned medium treated group. Intercellular adhesion molecule-1 was upregulated by microRNA-221 in mesenchymal stem cells because microRNAs are key regulators of various biological functions via gene expression. To investigate the effects in vivo, evaluation of bone regeneration by computed tomography and histological assays revealed that osteogenesis was enhanced in the hypoxic conditioned medium group relative to the other groups. These results suggest that behavioral changes of endogenous mesenchymal stem cells through microRNA-221 targeted-intercellular adhesion molecule-1 expression under hypoxic conditions may be a potential treatment for patients with bone defects.  相似文献   
37.
以清洁级ICR雄性小白鼠为实验动物,研究不同剂量乙酸铜对小白鼠的生殖毒性。采用小白鼠精子畸形实验及小白鼠骨髓嗜多染红细胞(以下简称PCE)微核实验等方法。分别对成年小白鼠腹腔每天注射0.25~16.00mg/kg8个剂量的乙酸铜,染毒7天。结果表明:乙酸铜对小白鼠的体重增长及睾丸重量具有一定的抑制作用,其中组VI、组VII的最明显。不同剂量的乙酸铜均使雄性小白鼠精子密度(P<0.001)、精子活力明显降低,具有明显的剂量效应。各实验组精子畸形率、PCE微核率均明显高于对照组(P<0.001)(P<0.05或P<0.001),且均随乙酸铜剂量的增加而明显升高。结果表明实验剂量的乙酸铜对ICR雄性小白鼠具有明显的生殖毒性效应。  相似文献   
38.
39.
BackgroundA 54-year-old woman presented with varus ankle arthritis, which was corrected with total ankle arthroplasty (TAA). Immediately postoperatively, she was insensate throughout the plantar foot. After seven weeks, she underwent tarsal tunnel release, and the tibial nerve was found to be intact. Plantar sensation improved by one week after exploration with neurolysis and was completely intact at one year.ConclusionLoss of plantar sensation can occur following TAA for varus arthritic deformity. One potential cause is tibial nerve compression from tightening the laciniate ligament, resulting in acute tarsal tunnel syndrome. The condition can be remedied with early recognition and tarsal tunnel release. Level of Evidence: V  相似文献   
40.
BackgroundThere is limited literature evaluating the impact of isolated cannabis use on outcomes for patients following spinal surgery. This study sought to compare 90-day complication, 90-day readmission, as well as 2-year revision rates between baseline cannabis users and non-users following thoracolumbar spinal fusion (TLF) for adult spinal deformity (ASD).MethodsThe New York Statewide Planning and Research Cooperative System (SPARCS) database was queried between January 2009 and September 2013 to identify all patients who underwent TLF for ASD. Inclusion criteria were age ≥18 years and either minimum 90-day (for complications and readmissions) or 2-year (for revisions) follow-up surveillance. Cohorts were created and propensity score-matched based on presence or absence of isolated baseline cannabis use. Baseline demographics, hospital-related parameters, 90-day complications and readmissions, and two-year revisions were retrieved. Multivariate binary stepwise logistic regression identified independent outcome predictors.Results704 patients were identified (n=352 each), with comparable age, sex, race, primary insurance, Charlson/Deyo scores, surgical approach, and levels fused between cohorts (all, p>0.05). Cannabis users (versus non-users) incurred lower 90-day overall and medical complication rates (2.4% vs. 4.8%, p=0.013; 2.0% vs. 4.1%, p=0.018). Cohorts had otherwise comparable complication, revision, and readmission rates (p>0.05). Baseline cannabis use was associated with a lower risk of 90-day medical complications (OR=0.47, p=0.005). Isolated baseline cannabis use was not associated with 90-day surgical complications and readmissions, or two-year revisions.ConclusionIsolated baseline cannabis use, in the absence of any other diagnosed substance abuse disorders, was not associated with increased odds of 90-day surgical complications or readmissions or two-year revisions, though its use was associated with reduced odds of 90-day medical complications when compared to non-users undergoing TLF for ASD. Further investigations are warranted to identify the physiologic mechanisms underlying these findings. Level of Evidence: III  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号