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   39930篇
  免费   3056篇
  国内免费   1165篇
耳鼻咽喉   331篇
儿科学   732篇
妇产科学   1019篇
基础医学   4735篇
口腔科学   1182篇
临床医学   5005篇
内科学   4659篇
皮肤病学   672篇
神经病学   2489篇
特种医学   1792篇
外国民族医学   10篇
外科学   6191篇
综合类   5526篇
现状与发展   7篇
一般理论   6篇
预防医学   3043篇
眼科学   756篇
药学   2158篇
  25篇
中国医学   957篇
肿瘤学   2856篇
  2024年   60篇
  2023年   1693篇
  2022年   2406篇
  2021年   2779篇
  2020年   2835篇
  2019年   1780篇
  2018年   1429篇
  2017年   1605篇
  2016年   1636篇
  2015年   1934篇
  2014年   3285篇
  2013年   2960篇
  2012年   3173篇
  2011年   2999篇
  2010年   2594篇
  2009年   2197篇
  2008年   1311篇
  2007年   1595篇
  2006年   1257篇
  2005年   701篇
  2004年   408篇
  2003年   213篇
  2002年   254篇
  2001年   228篇
  2000年   203篇
  1999年   237篇
  1998年   209篇
  1997年   178篇
  1996年   206篇
  1995年   173篇
  1994年   119篇
  1993年   96篇
  1992年   123篇
  1991年   151篇
  1990年   158篇
  1989年   119篇
  1988年   160篇
  1987年   69篇
  1986年   31篇
  1985年   56篇
  1984年   62篇
  1983年   43篇
  1982年   47篇
  1981年   65篇
  1980年   40篇
  1979年   43篇
  1978年   27篇
  1977年   33篇
  1975年   28篇
  1974年   40篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Subtalar joint distraction arthrodesis has been recommended for the treatment of conditions such as nonunion or malunion of subtalar joint arthrodesis posttraumatic arthritis. Both conditions are difficult to treat, because the deformities created in the frontal and sagittal planes of these conditions are complex. If these malalignments are not addressed, ankle joint instability and wear occur over time. In general, either autograft or allograft bone has been used to perform distraction arthrodesis of the subtalar joint. Although studies have shown successful use, there have been complications. Autografts have resulted in donor site morbidity and limitations on graft size, and allografts have shown high nonunion rates. Both autografts and allografts have shown graft collapse over time. Recent literature has discussed the use of tantalum technology to span large defects in bone healing. Studies have shown that tantalum provides superior strength and bone incorporation compared with autografts and allografts. This case series presents 2 cases in which tantalum truss technology was used for distraction arthrodesis. Although this series is limited in patient numbers, both cases show effective graft incorporation with no loss in height over time and earlier return to activity compared with previous studies that used autograft and allograft wedges.  相似文献   
32.
BackgroundA majority of youth with Autism Spectrum Disorder (ASD) have disrupted sleep patterns, but there has been limited research examining factors associated with sleep in this population. Objective: The objective of this study was to compare demographic and lifestyle behaviors with sleep quality in youth with ASD. Methods: A total of 49 children (12.44 years; 78% male) with ASD wore the Actigraph GT9X accelerometer over seven days and nights to assess moderate to vigorous physical activity (MVPA), sedentary behavior (SB), total sleep duration, and sleep efficiency. Parents reported their child’s weekly amount of screen time and demographic information. Participants were classified according to whether they met sleep criteria for duration and efficiency (8–9 h of sleep duration and ≥85% sleep efficiency). T-tests and ANOVA were used to compare demographic and lifestyle factors between the groups. Results: Participants who meet both sleep duration and efficiency criteria had greater minutes of MVPA per day (113.65 min/day) than participants who only met sleep efficiency criteria (40.27 min/day) and participants who did not meet either sleep criteria (67.5 min/day; p < 0.0001). Additionally, participants who met both sleep criteria had fewer minutes of SB compared to those who only met sleep efficiency criteria (384.79 vs 526.05 min/day; p = 0.02). Conclusions: Youth who had indicators of good sleep quality had greater amounts of MVPA and lower amounts of SB. Studies should further examine the relationship between sleep and health behaviors in youth with ASD to determine causal mechanisms, leading to more effective sleep interventions.  相似文献   
33.
34.
35.
《The Journal of arthroplasty》2019,34(8):1711-1717
BackgroundThe declining popularity of cemented acetabular components is incongruous, given the published results of prostheses implanted using contemporary techniques. The outcome of arthroplasty has previously been demonstrated to correlate with surgeon experience and volume of practice. We aim to explore if surgeon volume alters outcomes of cemented acetabular components based on survivorship data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR).MethodsAn observational study was undertaken using a cohort of 22,956 patients with a primary diagnosis of osteoarthritis in the period 2003-2016 in whom cemented acetabular components were implanted. The cohort was stratified by age (greater than or less than 65 years) and annualized surgical volume of ≤10, >10-≤25, and >25 cases.ResultsStratified by age and volume, there was a protective benefit against revision conveyed at volume thresholds of 10 cases per annum and 25 cases per annum for patients ≥65 years of age and <65 years of age, respectively.ConclusionCemented total hip arthroplasty has excellent survivorship out to 15 years based on AOANJRR data. This survivorship is further improved if surgeons perform a higher volume of cases, with >25 cases conferring the greatest benefit. The AOANJRR data set is used to define best practice; surgeons who choose to utilize cemented acetabular fixation should be encouraged to perform this technique in adequate volumes to minimize revision risk and ensure the preservation of this important surgical skill set.  相似文献   
36.
37.
38.
IntroductionReverse shoulder arthroplasty (RSA) alters normal anatomic relationships and results in increased deltoid forces. Which alter physiologic stress patterns in the acromion resulting in fractures. The purpose of this study was to evaluate the effect of acromion anatomy on the stress levels and risk of acromial fracture after RSA.MethodsA lateralization onlay design of the Exactech Equinoxe RSA standard stem was used for all four different acromial sizes (ranging from −5.0 mm to +5.0 mm) and compared to standard normal shoulder model (acromial size 0). A finite element analysis (FEA) model was then constructed for each case and quasi-static analysis was carried out to determine the highest minimum principal stress (HMPS) for each case and this was used to predict fatigue life percentage (FLP) of the acromion.ResultsFor smaller acromion sizes of −5 mm and -2.5 mm, the HMPS was found to be 1.87 and 1.24 times higher than the standard, respectively. The HMPS for the +2.5 mm acromial size was 0.95 times compared to the standard and 1.04 times higher for the +5 mm acromial size. According to our model, the highest FLP was seen when the acromion size was +2.5 mm (case 4 - 178%) and the lowest FLP was seen when it was -5 mm (−0.06%).ConclusionOur results suggest that there is an optimal acromion size (+2.5 mm from normal male) that leads to the lowest fracture risk in RSA. Surgeons must be aware of acromion size as a critical factor in deltoid tensioning, acromial stress, and risk of acromial fracture when selecting optimal implant designs and sizes for RSA.Level of evidence: Basic Science Study  相似文献   
39.
目的以基因表达数据集资料为研究对象,分析BCAN基因在肾透明细胞癌中的表达情况以及对患者预后的影响。方法在Oncomine数据库中挖掘BCAN在肾透明细胞癌(ccRCC)中的表达情况。从TCGA数据库中获取ccRCC患者临床资料和目的基因的表达信息并进行统计分析。利用GEO数据库中GSE73731数据集的ccRCC样本进行基因富集分析。利用String数据库分析与BCAN相关的蛋白。结果BCAN低表达组的ccRCC患者在病理分期及T分期方面低于高表达组(P<0.001;P=0.001);N分期及M分期差异无统计学意义(P>0.05)。BCAN低表达组患者的总生存期优于高表达组(P=0.033)。BCAN基因高表达组的样本主要富集在KRAS信号通路。结论BCAN可以通过多种途径来促进肿瘤细胞的侵袭能力,有望成为ccRCC不良预后的重要生物标志物之一。  相似文献   
40.
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