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   766篇
  免费   38篇
  国内免费   20篇
耳鼻咽喉   1篇
儿科学   35篇
妇产科学   6篇
基础医学   93篇
口腔科学   28篇
临床医学   76篇
内科学   177篇
皮肤病学   5篇
神经病学   69篇
特种医学   114篇
外科学   29篇
综合类   11篇
预防医学   52篇
眼科学   5篇
药学   61篇
中国医学   3篇
肿瘤学   59篇
  2021年   11篇
  2020年   2篇
  2019年   13篇
  2018年   9篇
  2017年   7篇
  2016年   13篇
  2015年   16篇
  2014年   17篇
  2013年   31篇
  2012年   21篇
  2011年   16篇
  2010年   35篇
  2009年   33篇
  2008年   25篇
  2007年   27篇
  2006年   25篇
  2005年   20篇
  2004年   26篇
  2003年   19篇
  2002年   19篇
  2001年   10篇
  2000年   18篇
  1999年   12篇
  1998年   30篇
  1997年   34篇
  1996年   28篇
  1995年   25篇
  1994年   27篇
  1993年   21篇
  1992年   11篇
  1991年   8篇
  1990年   15篇
  1989年   23篇
  1988年   28篇
  1987年   22篇
  1986年   22篇
  1985年   19篇
  1984年   13篇
  1983年   12篇
  1982年   16篇
  1981年   11篇
  1980年   6篇
  1979年   3篇
  1978年   5篇
  1977年   1篇
  1976年   3篇
  1975年   9篇
  1969年   3篇
  1967年   1篇
  1941年   1篇
排序方式: 共有824条查询结果,搜索用时 15 毫秒
71.
经皮椎体注入骨水泥治疗老年脊椎骨质疏松压缩性骨折   总被引:4,自引:0,他引:4  
目的:观察经皮椎体内注入骨水泥(聚甲基丙烯酸甲酯)治疗脊椎骨质疏松压缩性骨折的疗效。方法:自2005-06/2006-06吉林大学中日联谊医院骨科及大庆龙南医院骨科对35例40个椎体的骨质疏松压缩性骨折患者使用经皮椎体内注射骨水泥,行椎体成形术。成形材料:美国KYPHON公司生产的骨水泥,生产准许号:(GB/T19001-2000和YY/T0287-1996)。结果:35例患者均参加随访6个月。术后均未出现骨水泥外漏、脊髓或马尾神经损伤等并发症。35例患者中5例出现穿刺部位局部疼痛,服用镇痛药物后均缓解。疼痛完全消失25例,占71.4%;明显缓解8例,占22.6%;轻度缓解2例,占6.0%;无缓解0例。15例患者在术后72h内均能下床活动。术后未再发生压缩性骨折及疼痛。结论:经皮椎体注入骨水泥可以有效改善椎体骨质疏松压缩性骨折患者疼痛症状,随访6个月未出现充填剂不良性宿主反应,临床疗效较好。  相似文献   
72.
目的观察老年冠心病患者(包括高龄老年患者)冠状动脉影像学特点和临床特征,分析老年冠心病各危险因素与冠状动脉病变程度的相关性。方法选择冠状动脉造影确诊为冠心病的患者280例,按年龄不同分为3组:中年组(〈60岁),普通老年组(60岁≤年龄〈75岁),高龄老年组(≥75岁)。所有患者均在入院后测定空腹血糖、血脂、尿酸等生化指标;测量身高、体重;调查既往史;同期行冠状动脉造影及超声心动图检查。冠状动脉狭窄程度根据美国心脏协会(AHA)1975年分类标准评价,冠状动脉的危险因素应用Spearman相关分析。结果①普通与高龄老年组冠状动脉积分较中年组高,高龄老年组最明显(P〈0.01);普通与高龄老年组右冠状动脉(RCA)病变比例均升高,高龄老年组右冠状动脉积分高于普通老年组(P〈0.05)。②普通与高龄老年组左心室射血分数(LVEF)均较中年组明显减低(P〈0.05),高龄老年组比普通老年组更低(P〈0.05)。③年龄、左心室质量指数、左心室射血分数、空腹血糖水平、低密度脂蛋白胆固醇水平及高血压、糖尿病、心肌梗死病史与冠状动脉积分明显相关。结论老年冠心病患者冠状动脉病变广泛而严重,且心功能差,高龄老年患者更明显;年龄因素不可控制,因此积极干预其他危险因素如高血压、糖尿病、高血脂等甚为重要。  相似文献   
73.

Background Context

Recombinant human bone morphogenetic protein 2 (rhBMP-2) plays a pivotal role in complex spine surgery. Despite its limited approval, the off-label use of rhBMP-2 is prevalent, particularly in transforaminal lumbar interbody fusions (TLIFs).

Purpose

To determine the effectiveness and safety of rhBMP-2 use in TLIF procedures versus autograft.

Study Design

Retrospective cohort study.

Patient Sample

Patients older than 18 years undergoing spine surgery for lumbar degenerative spine disease at a single academic institution.

Outcome Measures

Clinical outcome was determined according to patient records. Radiographic outcome was determined according to plain X-rays and computed tomography (CT).

Methods

A retrospective study from 1997 to 2014 was conducted on 191 adults undergoing anterior-posterior instrumented spinal fusion with TLIF at a single academic institution. Patient data were gathered from operative notes, follow-up clinic notes, and imaging studies to determine complications and fusion rates. One hundred eighty-seven patients fit the criteria, which included patients with a minimum of one TLIF, and had a minimum 2-year radiographic and clinical follow-up. Patients were further classified into a BMP group (n=83) or non-BMP group (n=104). Three logistic regression models were run using rhBMP-2 exposure as the independent variable. The respective outcome variables were TLIF-related complications (radiculitis, seroma, osteolysis, and ectopic bone), surgical complications, and all complications.

Results

Bone morphogenetic protein (n=83) and non-BMP (n=104) groups had similar baseline demographics (sex, diabetes, pre-existing cancer). On average, the BMP and non-BMP groups were similarly aged (51.9 vs. 47.9 years, p>.05), but the BMP group had a shorter follow-up time (3.03 vs. 4.06 years; p<.001) and fewer smokers (8 vs. 21 patients; p<.048). The fusion rate for the BMP and non-BMP groups was 92.7% and 92.3%, respectively. The pseudoarthrosis rate was 7.5% (14 of 187 patients). Radiculitis was observed in seven patients in the BMP group (8.4%) and two patients in the non-BMP group (1.9%). Seroma was observed in two patients in the BMP group (2.4%) and none in the non-BMP group. No deep infections were observed in the BMP group, and in one patient in the non-BMP group (0.96%). Although patients exposed to BMP were at a significantlygreater risk of developing radiculitis and seroma (odds ratio [OR]=4.53, confidence interval [CI]=1.42–14.5), BMP exposure was not a significant predictor of surgical complications (OR=0.32, CI=0.10–1.00) or overall complications (OR=1.11, CI=0.53–2.34). The outcome of TLIF-related complications was too rare and the confidence interval too wide for practical significance of the first model.

Conclusion

Evidence supports the hypothesis that off-label use of rhBMP-2 in TLIF procedures is relatively effective for achieving bone fusion at rates similar to patients receiving autograft. Patients exhibited similar complication rates between the two groups, with the BMP group exhibiting slightly higher rates of radiculitis and seroma.  相似文献   
74.
目的:观察低血糖指数的膳食对2型糖尿病患者氧化应激状态的影响。方法:2004-10/11在上海市静安区二个社区卫生服务中心招募受试者,经医生明确诊断为2型糖尿病、病程超过6个月,体质量指数≥24kg/m2的老年糖尿病志愿者43名,受试者对试验知情同意。采用随机交叉试验随机分配至低血糖指数饮食组和高血糖指数饮食组,每种膳食分别连续使用4周,间隔洗脱期4周,比较试验前后患者超氧化物歧化酶、脂质过氧化产物丙二醛和谷胱甘肽过氧化物酶含量的变化。结果:受试者依从性好,除1人因试验期间发现肿瘤而退出试验,42名志愿者按设计要求完成试验。膳食干预后低血糖指数饮食组和高血糖指数饮食组的超氧化物歧化酶活力分别升高了15.68%和21.33%,丙二醛水平分别下降23.94%和21.55%,谷胱甘肽过氧化物酶活力分别升高了15.74%和17.09%;干预后低血糖指数饮食组丙二醛下降水平与高血糖指数饮食组比较差异有显著性意义(P<0.05),而超氧化物歧化酶和谷胱甘肽过氧化物酶活性两组间差异无显著性意义(P>0.05)。结论:在控制总能量的基础上给予平衡膳食能够改善其氧化应激水平,采用低血糖指数食物有助于氧化应激水平的改善。  相似文献   
75.
目的:分析力学刺激体外骨髓间充质干细胞所产生增殖分化等生物学效应的影响及其力化学信号转导途径。资料来源:因特网上检索PubMed数据库中2000-01/2006-06期间有关力学刺激对骨髓干细胞作用效应进展的英文文章,检索词“stem cel1,marrow mesenchymal stem cells,mechanical stimulation,stress”,同时检索CNKI中国知网医学文献数据库2000-01/2006-06期间的相关文章,检索词为“干细胞、骨髓间充质干细胞、机械刺激、应力”。资料选择:对资料进行筛选,选取相关文章查找全文。纳入标准:①骨髓间充质干细胞相关生物学特性。②体外细胞加载的应力分类及相应力学装置的特点。③应力对细胞影响的研究。④能获取文章的全文。排除标准:①较陈旧的文献。②重复研究。资料提炼:共收集关于86篇体外骨髓干细胞及力学干预的相关文献。其中30篇符合纳入标准。资料综合:①骨髓干细胞具有高度增殖及多向分化能力,可通过体外培养、干预作为细胞组织工程的理想种子细胞。②力学刺激是体外调节细胞生物学效应的重要途径,其中力学分类有:流体切应力、静止压应力、张应力、离心力以及单个细胞的吸吮力等,介绍各种力以及相应的力学装置的特点。③骨髓干细胞加载各种应力干预后产生的生物学效应,以及细胞应力学刺激的机制、信号转导途径。结论:力学刺激可影响骨髓间充质干细胞生物学特性,在适当的力学刺激条件下,促进细胞的增殖与分化,为骨组织工程提供新的技术手段,同时也为临床应用牵拉成骨的骨再生过程提供理论依据。  相似文献   
76.
目的:分析血管紧张素原基因启动子区A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压的相关性。方法:实验于2005-08/2006-01在北京华大实验室完成。选取对象均为生活在内蒙古乌拉特后旗的蒙古族牧民,三代血亲内无其他民族。采用基因测序技术对内蒙古蒙古族人群中107例原发性高血压患者和108例正常对照者进行A-20C和A-6G基因分型,观察高血压组和正常对照组不同基因型的分布和等位基因频率的差异。结果:①两组受试者在性别、年龄及吸烟、饮酒、体质量指数和临床化验检查指标有较好的匹配(P均>0.05)。②两组血管紧张素原基因A-20C位点AA,AC,CC基因型频率比较差异无显著性意义(高血压组分别为0.51,0.29,0.20;正常对照组分别为0.49,0.28,0.23,χ2=0.395,P=0.529)。A,C等位基因频率比较差异无显著性意义(高血压组分别为0.65,0.35;正常对照组分别为0.63,0.37,χ2=0.015,P=0.904)。③两组血管紧张素原基因A-6G位点AA,AG,GG基因型频率比较差异无显著性意义(高血压组分别为0.50,0.33,0.17;正常对照组分别为0.55,0.34,0.11,χ2=1.924,P=0.165)。A,G等位基因频率比较差异无显著性意义(高血压组分别为0.66,0.34;正常对照组分别为0.72,0.28,χ2=1.728,P=0.189)。④高血压组协同存在血管紧张素原基因A-20C基因型CC时,血管紧张素原基因A-6G基因型GG频率稍高于正常对照组,但差异无显著性意义(χ2=2.395,P=0.122,OR=7.52,95%CI0.014~1.250),高血压组G等位基因明显高于正常对照组(分别为0.37,0.22,χ2=4.658,P=0.034),携带该等位基因的蒙古族人群发生原发性高血压的相对危险度升高(OR=2.80,95%CI1.087~7.271)。结论:血管紧张素原基因A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压相关,并可能具有协同作用。  相似文献   
77.
Fibroblast growth factor (FGF) signaling has been implicated in the pathogenesis of pulmonary fibrosis. Mice lacking FGF2 have increased mortality and impaired epithelial recovery after bleomycin exposure, supporting a protective or reparative function following lung injury. To determine whether FGF2 overexpression reduces bleomycin‐induced injury, we developed an inducible genetic system to express FGF2 in type II pneumocytes. Double‐transgenic (DTG) mice with doxycycline‐inducible overexpression of human FGF2 (SPC‐rtTA;TRE‐hFGF2) or single‐transgenic controls were administered intratracheal bleomycin and fed doxycycline chow, starting at either day 0 or day 7. In addition, wild‐type mice received intratracheal or intravenous recombinant FGF2, starting at the time of bleomycin treatment. Compared to controls, doxycycline‐induced DTG mice had decreased pulmonary fibrosis 21 days after bleomycin, as assessed by gene expression and histology. This beneficial effect was seen when FGF2 overexpression was induced at day 0 or day 7 after bleomycin. FGF2 overexpression did not alter epithelial gene expression, bronchoalveolar lavage cellularity or total protein. In vitro studies using primary mouse and human lung fibroblasts showed that FGF2 strongly inhibited baseline and TGFβ1‐induced expression of alpha smooth muscle actin (αSMA), collagen, and connective tissue growth factor. While FGF2 did not suppress phosphorylation of Smad2 or Smad‐dependent gene expression, FGF2 inhibited TGFβ1‐induced stress fiber formation and serum response factor‐dependent gene expression. FGF2 inhibition of stress fiber formation and αSMA requires FGF receptor 1 (FGFR1) and downstream MEK/ERK, but not AKT signaling. In summary, overexpression of FGF2 protects against bleomycin‐induced pulmonary fibrosis in vivo and reverses TGFβ1‐induced collagen and αSMA expression and stress fiber formation in lung fibroblasts in vitro, without affecting either inflammation or epithelial gene expression. Our results suggest that in the lung, FGF2 is antifibrotic in part through decreased collagen expression and fibroblast to myofibroblast differentiation. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.  相似文献   
78.
79.

Problem

A multinational company with operations in several African countries was committed to offer antiretroviral treatment to its employees and their dependants.

Approach

The Accelerating Access Initiative (AAI), an initiative of six pharmaceutical companies and five United Nations’ agencies, offered the possibility of obtaining brand antiretroviral drugs (ARVs) at 10% of the commercial price. PharmAccess, a foundation aimed at removing barriers to AIDS treatment in Africa, helped to establish an HIV policy and treatment guidelines, and a workplace programme was rolled out from September 2001.

Local setting

Private sector employers in Africa are keen to take more responsibility in HIV prevention and AIDS care. An important hurdle for African employers remains the price and availability of ARVs.

Relevant changes

The programme encountered various hurdles, among them the need for multiple contracts with multiple companies, complex importation procedures, taxes levied on ARVs, lack of support from pharmaceutical companies in importation and transportation, slow delivery of the drugs, lack of institutional memory in pharmaceutical companies and government policies excluding the company from access to ARVs under the AAI.

Lessons learned

The launch of the AAI enabled this multinational company to offer access to ARVs to its employees and dependants. The private sector should have access to these discounted drugs under the AAI. A network of local AAI offices should be created to assist in logistics of drugs ordering, purchase and clearance. No taxes should be levied on ARVs.  相似文献   
80.

Background  

A recent in vitro study indicates that IGOB131, a novel seed extract of the traditional West African food plant Irvingia gabonensis, favorably impacts adipogenesis through a variety of critical metabolic pathways including PPAR gamma, leptin, adiponectin, and glycerol-3 phosphate dehydrogenase. This study was therefore aimed at evaluating the effects of IGOB131, an extract of Irvingia gabonensis, on body weight and associated metabolic parameters in overweight human volunteers.  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