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   104792篇
  免费   8635篇
  国内免费   3545篇
耳鼻咽喉   403篇
儿科学   2584篇
妇产科学   854篇
基础医学   12689篇
口腔科学   1620篇
临床医学   9407篇
内科学   23157篇
皮肤病学   1563篇
神经病学   5551篇
特种医学   2596篇
外国民族医学   6篇
外科学   15717篇
综合类   14268篇
现状与发展   9篇
一般理论   1篇
预防医学   6029篇
眼科学   1437篇
药学   10923篇
  48篇
中国医学   4857篇
肿瘤学   3253篇
  2024年   257篇
  2023年   1582篇
  2022年   2292篇
  2021年   3989篇
  2020年   3712篇
  2019年   4058篇
  2018年   3932篇
  2017年   3925篇
  2016年   4080篇
  2015年   4013篇
  2014年   7451篇
  2013年   7878篇
  2012年   6754篇
  2011年   7239篇
  2010年   5483篇
  2009年   5358篇
  2008年   5018篇
  2007年   5000篇
  2006年   4441篇
  2005年   3883篇
  2004年   3175篇
  2003年   2710篇
  2002年   2286篇
  2001年   1996篇
  2000年   1652篇
  1999年   1454篇
  1998年   1243篇
  1997年   1179篇
  1996年   961篇
  1995年   873篇
  1994年   783篇
  1993年   647篇
  1992年   587篇
  1991年   462篇
  1990年   369篇
  1989年   327篇
  1988年   287篇
  1987年   267篇
  1986年   229篇
  1985年   595篇
  1984年   661篇
  1983年   522篇
  1982年   517篇
  1981年   481篇
  1980年   419篇
  1979年   373篇
  1978年   319篇
  1977年   244篇
  1976年   284篇
  1975年   268篇
排序方式: 共有10000条查询结果,搜索用时 437 毫秒
91.
92.
PurposeOptimum management of displaced intra-articular calcaneal fractures (DIACF) still controversial. Open surgery carries the risk of wound complications, while non-operative management has a high incidence of arthrosis. To avoid these complications, minimally invasive and percutaneous fixation was introduced. The purpose of this study was to prospectively evaluate the short term clinical and radiological outcomes after closed reduction and percutaneous fixation of DIACF using K-wires.Patients and methodsOutcomes of twenty patients were evaluated at the final follow up. A functional assessment using the AOFAS scoring system. Radiological parameters recorded included three angles (Böhler’s, Gissane and posterior facet inclination angles) and three distances (calcaneal length, height and width). Any complications were reported at any follow-up.ResultsThe mean patient’s age was 33 ± 15.2 years, 8 (40%) patients with type II fractures, 10 (50%) patients with type III fractures, and 2 (10%) with type IV fracture according to Sanders classification. After a mean follow-up of 9 months, the mean AOFAS score was 84, excellent in 9 patients (45%), good in 9 (45%), and fair in 2 (10%). At the final follow-up the Böhler’s angle, Gissane angle and PFIA was 25.1° ± (5.2), 119.9° ± (9.4) and 51.7° ± (5.9) respectively and the calcaneal height, length and width was 41.8 mm ± (2.1), 75.1 mm ± (3.01) and 40.9 mm ± (2.6) respectively. We had no cases of deep infection, 20% had significant subtalar arthritis.ConclusionThe closed reduction and percutaneous fixation technique for DIACF management offered acceptable clinical and radiographic outcomes, with fewer complications when compared to other management options.  相似文献   
93.
94.
95.
Taurodontism is a rare embryologic anomaly of teeth, defined by an apical displacement of the furcation of roots and enlarged pulp chambers. Taurodontism has been classified as hypo‐, meso‐ or hypertaurodontism according to the severity of the anomaly. The aim of this case report was to illustrate a clinical case with multiple bilateral taurodonts and to describe the endodontic management of the hypertaurodontic mandibular left second molar with a C‐shaped canal and extensive dental pulp calcifications. A healthy 20‐year‐old male patient was referred for the endodontic treatment of his lower left second molar. Cone beam computed tomography revealed a C‐shaped root canal configuration and several dental pulp calcifications in this tooth. The endodontic treatment was performed in two appointments under an operating dental microscope. A panoramic radiograph, made during the 18 months follow‐up appointment, revealed nine other taurodontic molars, most of them associated with dental pulp calcifications.  相似文献   
96.
《Value in health》2020,23(10):1340-1348
ObjectivesWe applied principles for conducting economic evaluations of factorial trials to a trial-based economic evaluation of a cluster-randomized 2 × 2 × 2 factorial trial. We assessed the cost-effectiveness of atorvastatin, omega-3 fish oil, and an action-planning leaflet, alone and in combination, from a UK National Health Service perspective.MethodsThe Atorvastatin in Factorial With Omega EE90 Risk Reduction in Diabetes (AFORRD) Trial randomized 800 patients with type 2 diabetes to atorvastatin, omega-3, or their respective placebos and randomized general practices to receive a leaflet-based action-planning intervention designed to improve compliance or standard care. The trial was conducted at 59 UK general practices. Sixteen-week outcomes for each trial participant were extrapolated for 70 years using the United Kingdom Prospective Diabetes Study Outcomes Model v2.01. We analyzed the trial as a 2 × 2 factorial trial (ignoring interactions between action-planning leaflet and medication), as a 2 × 2 × 2 factorial trial (considering all interactions), and ignoring all interactions.ResultsWe observed several qualitative interactions for costs and quality-adjusted life-years (QALYs) that changed treatment rankings. However, different approaches to analyzing the factorial design did not change the conclusions. There was a ≥99% chance that atorvastatin is cost-effective and omega-3 is not, at a £20 000/QALY threshold.ConclusionsAtorvastatin monotherapy was the most cost-effective combination of the 3 trial interventions at a £20 000/QALY threshold. Omega-3 fish oil was not cost-effective, while there was insufficient evidence to draw firm conclusions about action planning. Recently-developed methods for analyzing factorial trials and combining parameter and sampling uncertainty were extended to estimate cost-effectiveness acceptability curves within a 2x2x2 factorial design with model-based extrapolation.  相似文献   
97.
目的分析研究绝经后女性2型糖尿病伴骨质疏松症患者骨密度与骨代谢指标的相关性。方法选取2013年10月至2017年05月于重庆医科大学附属第一医院内分泌内科住院的绝经后女性2型糖尿病患者385名。搜集其基本资料、骨代谢指标及骨密度等。根据T值将这些患者分为骨质疏松组(233例)、骨量减少组(101例)和骨量正常组(51例),比较三组间骨代谢指标的变化,并对骨密度(bone mineral density,BMD)与各项骨代谢指标进行相关性分析。结果 1型前胶原氨基末端前肽(Type I procollagen N-terminal propeptide,P1NP)、骨钙素(bone Gla protein,BGP)在骨质疏松组显著高于骨量减少组、骨量正常组(P0.05);随着骨密度的降低,1型胶原羧基端肽β特殊序列(β-Carboxyl terminal peptide,β-CTX)逐渐升高,骨质疏松组、骨量减少组与骨量正常组相比较差异有统计学意义(P0.05);Spearman等级相关分析示P1NP、BGP、β-CTX与骨密度呈负相关,25(OH)D_3与骨密度呈现正相关。结论绝经后女性2型糖尿病伴骨质疏松症患者骨密度与骨代谢指标有一定的相关性,有助于预测骨折风险并及时抗骨质疏松治疗。  相似文献   
98.
目的研究续筋接骨方治疗骨折的临床疗效。方法选取2018年1月—2018年6月在辽宁中医药大学附属第三医院就诊的骨折患者60例,所有患者按照随机数字表法分为对照组与观察组,每组30例。观察组口服续筋接骨方联合正骨后小夹板固定治疗,对照组患者采用正骨后小夹板固定治疗。分析2组患者干预3个月后的血清骨代谢指标、骨密度、生活质量改善情况以及疗效判定。结果干预前,2组的血清Ⅰ型前胶原羧基端肽β特殊序列(β-CTX)、血清Ⅰ型前胶原氨端肽原(PINP)、骨特异性碱性磷酸酶(ALP)水平、钙、磷及骨密度比较,差异无统计学意义(P>0.05);干预后,2组的β-CTX、PINP、骨特异性ALP水平、钙、磷及骨密度较干预前改善,观察组的改善效果优于对照组,差异均有统计学意义(P<0.05)。干预前,2组的物质生活、社会功能、躯体健康以及心理健康评分比较,差异无统计学意义(P>0.05);干预后,2组的物质生活、社会功能、躯体健康以及心理健康评分较干预前升高,观察组的各项生活质量评分高于对照组,差异均有统计学意义(P<0.05)。观察组的治疗恢复率高于对照组,差异有统计学意义(P<0.05)。结论续筋接骨方可以改善骨折患者骨代谢功能及生活质量。  相似文献   
99.
ObjectiveMultiple treatment options for acetabular fractures in geriatric patients exist. However, no large-scale studies have reported the outcomes of acute total hip arthroplasty (THA) in this patient population. We systematically evaluated all available evidence to characterize clinical outcomes, complications, and revisions of acute THA for acetabular fractures in geriatric patients.MethodsMeta-analysis of 21 studies of 430 acetabular fractures with mean follow-up of 44 months (range, 17−97 months). Two independent researchers searched and evaluated the databases of Ovid, Embase, and United States National Library of Medicine using a Boolean search string up to December 2019. Population demographics and complications, including presence of heterotopic ossification (HO), dislocation, infection, revision rate, neurological deficits, and venous thromboembolic event (VTE), were recorded and analyzed.ResultsWeighted mean Harris Hip Score was 83.3 points, and 20% of the patients had reported complications. The most common complication was HO, with a rate of 19.5%. Brooker grade III and IV HO rates were lower at 6.8%. Hip dislocation occurred at a rate of 6.1%, 4.1% of patients developed VTE, deep infection occurred in 3.8%, and neurological complications occurred in 1.9%. Although the revision rate was described in most studies, we were unable to perform a survival analysis because the time to each revision was described in only a few studies. The revision rate was 4.3%.ConclusionsAcute THA is a viable option for treatment of acetabular fracture and can result in acceptable clinical outcomes and survivorship rates in older patients but with an associated complication rate of approximately 20%. Considering the limited treatment options, THA might be a viable alternative for appropriately selected patients.  相似文献   
100.
《Annals of hepatology》2020,19(2):190-196
Introduction and objectivesZinc deficiency has been associated with poor prognosis in chronic liver disease. This systematic review and meta-analysis aimed to evaluate the role of zinc supplementation in the management of chronic liver diseases.Materials and methodsWe searched MEDLINE, LILACS, EMBASE, and Cochrane CENTRAL databases from inception to August 2018. We included randomized controlled trials evaluating adult patients with chronic liver disease of any etiology receiving zinc supplementation. Studies with other designs or evaluating chronic conditions other than liver disease were excluded. Two reviewers independently screened and extracted data from eligible studies. Study quality was assessed using the Cochrane Collaboration's tool for assessing risk of bias in randomized studies.ResultsOf 1315 studies screened, 13 were included. Six assessed chronic hepatitis C treatment, with a relative risk of 0.83 indicating no protective effect of zinc supplementation on the improvement of sustained virological response. Three evaluated response to hepatic encephalopathy treatment, with a relative risk of 0.66 indicating a favorable effect of zinc supplementation on clinical improvement of this condition. Of four studies evaluating the management of cirrhosis, two analyzed the effect of zinc supplementation on serum albumin levels, with no statistical difference between zinc and placebo groups.ConclusionsClinical trials assessing zinc supplementation in liver diseases do not show benefits in terms of clinical improvement or disease halting. There are possible benefits of zinc supplementation on hepatic encephalopathy, however, this is based on limited evidence. This research question is still open for evaluation in larger, well-designed, clinical trials.  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