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   4988篇
  免费   317篇
  国内免费   74篇
耳鼻咽喉   68篇
儿科学   106篇
妇产科学   97篇
基础医学   397篇
口腔科学   324篇
临床医学   942篇
内科学   270篇
皮肤病学   19篇
神经病学   217篇
特种医学   188篇
外科学   990篇
综合类   691篇
预防医学   393篇
眼科学   141篇
药学   265篇
  8篇
中国医学   132篇
肿瘤学   131篇
  2024年   9篇
  2023年   92篇
  2022年   137篇
  2021年   248篇
  2020年   242篇
  2019年   159篇
  2018年   170篇
  2017年   198篇
  2016年   205篇
  2015年   225篇
  2014年   361篇
  2013年   325篇
  2012年   336篇
  2011年   308篇
  2010年   280篇
  2009年   233篇
  2008年   239篇
  2007年   243篇
  2006年   213篇
  2005年   151篇
  2004年   132篇
  2003年   124篇
  2002年   96篇
  2001年   71篇
  2000年   75篇
  1999年   54篇
  1998年   57篇
  1997年   44篇
  1996年   60篇
  1995年   18篇
  1994年   34篇
  1993年   29篇
  1992年   20篇
  1991年   25篇
  1990年   17篇
  1989年   20篇
  1988年   12篇
  1987年   16篇
  1986年   14篇
  1985年   16篇
  1984年   5篇
  1983年   7篇
  1982年   14篇
  1981年   9篇
  1980年   15篇
  1979年   3篇
  1977年   6篇
  1974年   4篇
  1973年   2篇
  1971年   2篇
排序方式: 共有5379条查询结果,搜索用时 109 毫秒
101.
目的探讨使用有效的测量工具和在适合的测量时间段采集侧卧手术体位老年患者基础数据,找出患者眼压变化随体位变化的规律,旨在制订有效的护理预防措施。方法选取2019年3—6月在首都医科大学附属北京同仁医院中心手术室完成胸科胸腔镜手术的老年患者31例。使用icare回弹式眼压计分别于患者入手术室后、全身麻醉插管后、侧卧5 min、侧卧30 min、术中1 h、术中2 h、术中3 h、翻身拔管、出室前9个时间点测量双眼眼压,同时记录每个时间点患者的血压、心率数据,记录手术过程中液体出入量、特殊用药等。结果患者侧卧5 min、侧卧30 min、术中1 h、术中2 h、术中3 h的血压与入室后比较,差异有统计学意义(P<0.05);不同时间点的心率比较,差异无统计学意义(P>0.05)。麻醉插管后患者双眼眼压均低于入室时眼压,差异有统计学意义(P<0.05);侧卧30 min、术中1 h、术中2 h、术中3 h的双眼眼压与入室后眼压比较,差异有统计学意义(P<0.05);侧卧5 min、侧卧30 min、术中1 h、术中2 h、术中3 h的受压侧眼压与非受压侧眼压比较,差异有统计学意义(P<0.05)。Pearson相关分析显示,患者平均动脉压与受压侧眼及非受压侧眼的眼压均无相关性(r值分别为-0.1138、0.0179,P>0.05)。进入手术间时患者测试视力与术后6 h回病房后测试视力比较,差异无统计学意义(P>0.05)。结论胸腔镜手术老年患者的眼压随手术体位变化而波动,从侧卧5 min开始眼压出现变化,2 h内受压侧眼眼压达到高峰,体位恢复平卧位后,眼压随即恢复到入室时水平。本研究未发现血压与眼压变化的相关性。  相似文献   
102.
《Injury》2023,54(7):110767
AimThis network meta-analysis aims to compare functional outcomes and complications between conservative treatment and surgery for distal radius fractures in patients aged 60 years and over.MethodsWe searched the PubMed, EMBASE, and Web of Science databases for randomized controlled trials (RCTs) assessing the effect of conservative treatment and surgery for distal radius fractures in patients aged 60 years and over. Primary outcomes included grip strength and overall complications. Secondary outcomes included Disabilities of the Arm, Shoulder, and Hand (DASH) scores, Patient-Rated Wrist Evaluation (PRWE) scores, wrist range of motion and forearm rotation, and radiographic assessment. All continuous outcomes were assessed using standardized mean differences (SMDs) with 95% confidence intervals (CIs), and binary outcomes were assessed using odds ratio (OR) with 95% CIs. The surface under the cumulative ranking curve (SUCRA) was used to determine a hierarchy of treatments. Cluster analysis was performed for grouping treatments based on the SUCRA values of primary outcomes.ResultsFourteen RCTs were included to compare conservative treatment, volar lockedplate (VLP), K-wires fixation, and external-fixation. VLP outperformed conservative treatment for 1-year and minimum 2-year grip strength (SMD; 0.28 [0.07 to 0.48] and 0.27 [0.02 to 0.53], respectively). VLP yielded the optimal grip strength at 1-year and minimum 2-year follow-up (SUCRA; 89.8% and 86.7%, respectively). In a subgroup analysis of patients aged 60 to 80 years old, VLP outperformed conservative treatment in DASH and PRWE scores (SMD, 0.33 [0.10, 0.56] and 0.23 [0.01, 0.45], respectively). In addition, VLP had the fewest complications (SUCRA = 84.3%). Cluster analysis suggested that VLP and K-wire fixation were more effective treatment groups.ConclusionEvidence to date demonstrates that VLP provides measurable benefits in grip strength and fewer complications to those 60 years of age and over, and that benefit is not reflected in current practice guidelines. There is a subgroup of patients where K-wire fixation outcomes are similar to those of VLP; defining this subgroup may yield substantial societal benefits.  相似文献   
103.
Two experiments were performed to study short-term acoustic recognition memory using synthesized binary tone patterns within a three-interval, three-alternative forced choice psycho-physical procedure. In Experiment 1, subjects showed as significant performance advantage in processing binary frequency patterns over intensity and duration patterns. In Experiment 2, we found that elements at the beginnings and ends of various length frequency pattern sequences were recognized better than those in the middle of the sequence (primacy and recency effects). Furthermore, we showed that performance on a serial position task may be a useful tool to demonstrate the limited capacity of information storage in acoustic short-term memory. Sensory memory typically has been examined using verbal stimuli and requiring immediate ordered recall. These results demonstrate the utility of studying sensory memory using complex nonverbal stimuli within a forced-choice recognition paradigm.  相似文献   
104.
The mechanisms by which chondrocytes modulate longitudinal bone growth are not well understood. This in vitro study investigated the effects of loading on the mRNA expression pattern of key molecular components of the growth-plate related to the extracellular matrix (type II and type X collagen) and the PTH-PTHrP feedback loop. Short-term static compressive loading was applied to rat proximal tibial growth-plate explants. Four age groups at specific developmental stages were investigated. The spatial variation in the mRNA expression was compared among loaded explants, their contralateral sham controls, and uncultured growth plates from normal animals. Basic cell metabolism (18S rRNA) was unaffected by load. Results indicated a narrower spatial distribution of mRNA expression of type II collagen throughout the growth plate; similarly, a narrowed distribution of expression of type X collagen was noted in the lower hypertrophic zone of the growth-plate. This suggests that mechanical compression influences chondrocytes of the hypertrophic zone to alter their expression of specific genes encoding proteins of the extracellular matrix, while PTH-PTHrP receptor mRNA, a regulatory protein, remained unaffected by loading. The effects of compression were similar at the different stages of growth, suggesting that additional factors may be involved in the clinical progression of skeletal deformities observed during growth spurts. Although this study was done in vitro and limited to static loading, it furthers our understanding of growth-plate mechanobiology as a first step toward providing a scientific rationale for treating progressive musculoskeletal deformities.  相似文献   
105.
目的:探讨斜仰半截石位顺行微创经皮肾镜取石术(mPCNL)与逆行输尿管镜共同治疗输尿管多发结石的可行性、疗效与安全性。方法:分析2010年8月~2011年7月采用B超引导行mPCNL与输尿管镜结合同时治疗输尿管多发结石患者10例的临床资料。结果:10例均获得良好疗效,B超引导穿刺全部成功,mPCNL与输尿管镜同时处理输尿管多发结石,无严重并发症发生。结论:斜仰半截石位顺行微创经皮肾镜取石术与逆行输尿管镜共同治疗输尿管多发结石手术创伤小,疗效满意,值得在临床推广应用。  相似文献   
106.
《Primary Care Diabetes》2014,8(4):322-329
AimsTo examine whether socioeconomic position (SEP) was associated with change in cardiovascular risk factors and meeting treatment targets for cardiovascular risk factors among individuals with screen-detected Type 2 DM at six-year follow-up.MethodsThe study population was 1533 people with Type 2 DM identified from at stepwise diabetes screening programme in general practice during 2001–2006 in the ADDITION-Denmark study. The ADDITION-study was performed as a randomised trial but the two randomisation groups were analysed as one cohort in this study. Cardiovascular risk factors were measured at baseline and repeated at follow-up (mean: 5.9 [1.4] years). Information on SEP, redeemed antihypertensive and lipid-lowering treatment were obtained from Danish registers. Multivariate analyses were performed to estimate change in cardiovascular risk factors and difference in meeting treatment targets.ResultsThe change in HbA1c, cholesterol, blood pressure and BMI were virtually the same across educational level, income level, occupational status or cohabiting status. Overall, the ability to meet treatment targets for HbA1c, cholesterol and blood pressure was not modified by SEP-group. A higher proportion of people with lower educational level or lower income level in the intensive care redeemed anti-hypertensive treatment compared to people with higher educational or income levels.ConclusionScreen-detection and early treatment onset did not introduce socioeconomic inequality in metabolic control in people with screen-detected Type 2 DM at six-year follow-up.  相似文献   
107.
108.
Neglect patients' performance during cancellation tasks is characterized by left sided omissions and, in many cases, by the production of inappropriate material of various kinds in the ipsilesional space, e.g. additional marks over already cancelled targets, marks drawn away from targets, scribbles, irrelevant drawings. It is unclear whether these behaviours, which have collectively been called perseverative, are functionally and anatomically connected and whether they correlate with the severity of neglect. Here we report a retrospective study on 33 right brain damaged patients with neglect after right hemisphere lesions in whom we measured the intensity of perseveration of the three following kinds: (1) ‘additional marks' (AM) perseveration where patients cancelled a target with two or more well separated marks; (2) ‘scribble’ perseveration, where patients, instead of cancelling the target with a single pen stroke as required by the task, performed multiple pen strokes without breaking the pen-to-paper contact, with the final product being a scribble; (3) ‘flying marks’ (FM) perseveration where patients produced cancellation marks well away from the targets. We found that AM and FM perseveration correlated with neglect severity, while ‘scribble’ perseveration did not. The lesion-symptom mapping showed three separate anatomical areas in the right hemisphere: ‘scribble’ perseveration was associated with lesions of the orbitofrontal cortex and caudate nucleus; AM perseveration was associated with damage to the rolandic operculum, superior temporal gyrus and inferior frontal gyrus; FM perseveration was associated with damage to the dorsal premotor cortex and the temporal pole. Neglect severity followed damage to a region which grossly corresponds to the sum of the regions associated with AM and FM perseveration respectively. This complex behavioural and anatomical pattern is interpreted in terms of a three-factor model, in which AM perseveration is caused by a deficit of disengagement of attention from the right side (also causing omissions), FM perseveration is caused by directional hypokinesia (also causing left-side omissions), and ‘scribble’ perseveration is the consequence of a failure to inhibit an initiated motor act, which is completely separate (both anatomically and functionally) from the disorder inducing omissions.  相似文献   
109.
目的:探讨旷置螺钉孔对钢板螺丝钉内固定系统稳定性和骨折愈合的影响。方法:回顾性分析2010年3月-2012年3月收治的60例四肢骨干骨折患者的临床资料,根据是否主动旷置螺钉孔分为旷置组和非旷置组,每组各30例。分析比较两组患者总的疗效,包括:骨痂出现时间、骨折愈合时间(临床愈合、骨性愈合)、内固定失效率(骨不连发生率、钢板断裂发生率)、临床疗效等方面进行比较分析。结果:两组总疗效比较,旷置组优于非旷置组。临床疗效优良率:旷置组为93.3%,非旷置组为80%,两组比较差异有统计学意义(P〈0.05)。术后出现骨痂时间:旷置组为(9.16±1.70)周,非旷置组为(11.20±1.60)周,两组比较差异有统计学意义(P〈0.05);临床愈合时间:旷置组为(12.82±2.68)周,非旷置组为(15.36±3.66)周,两组比较差异有统计学意义(P〈0.05);骨性愈合时间:旷置组为(4.51±1.46)个月,非旷置组为(7.06±1.21)个月,两组比较差异有统计学意义(P〈0.05);术后旷置组骨不连发生率为0,非旷置组为3.3%;旷置组钢板断裂发生率为0,非旷置组为3.3%。结论:合理使用旷置螺钉孔技术对钢板螺丝钉内固定系统稳定性没有显著性影响,符合生物学固定原则;同时,由于有效保护骨折断端的血运,促进了骨折的愈合,减少骨不连、钢板断裂现象,是一种简单可行的操作技术,值得基层医院推广。  相似文献   
110.
目的比较髓内钉和钢板两种内固定治疗肱骨近端骨折的安全性、有效性及差异性。方法计算机检索Pub Med、CENTRAL、EMbase、the ISI Web of Knowledge Databases、VIP、CNKI、CBM和万方数据库,查找所有比较髓内钉和钢板钢板治疗肱骨近端骨折的随机对照试验(RCT)及临床对照试验(CCT),检索时限均为建库至2015年12月31日。同时手检纳入文献的参考文献。按纳入排除标准由两人独立进行筛选、资料提取和质量评价后,采用Rev Man5.3软件进行Meta分析。结果共纳入14个研究,1010例患者。Meta分析结果显示:与钢板相比,髓内钉治疗手术时间更短[MD=-23.04,95%CI(-28.47,-17.60),P0.1]、术中出血量较少[SMD=-3.14,95%CI(-4.21,-2.08),P0.1]、骨折愈合时间更短[SMD=-3.03,95%CI(-3.77,-2.28),P0.1],总的并发症无统计学意义[RR=0.38,95%CI(0.25,0.57),P=0.24];然而,ASES评分显示钢板组优于髓内钉组[SMD=-0.63,95%CI(-0.98,-0.28),P0.1],Costant-Murley评分差异无统计学意义[SMD=-0.05,95%CI(-0.21,0.11),P0.1],末次随访时颈干角差异无统计学意义[MD=0.09,95%CI(-0.22,0.40),P0.1],末次随访时Neer征差异无统计学意义[RR=0.51,95%CI(0.25,1.03),P0.1]。结论本系统研究发现,总体而言,治疗肱骨近端骨折时,髓内钉优于钢板。但这一结论仍然需要大样本、高质量的研究及采用关键性指标,进行进一步的论证。  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