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   18027篇
  免费   1165篇
  国内免费   504篇
耳鼻咽喉   190篇
儿科学   380篇
妇产科学   103篇
基础医学   1856篇
口腔科学   527篇
临床医学   1991篇
内科学   2281篇
皮肤病学   174篇
神经病学   2725篇
特种医学   2160篇
外科学   1648篇
综合类   1535篇
预防医学   660篇
眼科学   120篇
药学   1921篇
  6篇
中国医学   972篇
肿瘤学   447篇
  2024年   12篇
  2023年   229篇
  2022年   473篇
  2021年   869篇
  2020年   648篇
  2019年   623篇
  2018年   683篇
  2017年   634篇
  2016年   647篇
  2015年   696篇
  2014年   1359篇
  2013年   1426篇
  2012年   1145篇
  2011年   1345篇
  2010年   1009篇
  2009年   1009篇
  2008年   1007篇
  2007年   846篇
  2006年   778篇
  2005年   717篇
  2004年   540篇
  2003年   435篇
  2002年   349篇
  2001年   293篇
  2000年   249篇
  1999年   228篇
  1998年   187篇
  1997年   175篇
  1996年   136篇
  1995年   157篇
  1994年   140篇
  1993年   127篇
  1992年   93篇
  1991年   60篇
  1990年   61篇
  1989年   44篇
  1988年   42篇
  1987年   30篇
  1986年   21篇
  1985年   30篇
  1984年   18篇
  1983年   21篇
  1982年   22篇
  1981年   16篇
  1980年   8篇
  1979年   7篇
  1978年   12篇
  1977年   8篇
  1976年   9篇
  1975年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Background:We aim to evaluate the efficiency of Raman spectroscopy (RS) in diagnosing suspected patients with intrahepatic cholangiocarcinoma (ICC), manifested by diagnostic sensitivity, specificity, and accuracy.Methods:We will research widely the articles concerning the use of RS in ICC through authenticated database including PubMed/Medline, EMBASE, Web of Science, Ovid, Web of Knowledge, Cochrane Library, and CNKI between January 2012 and November 2020, retrieving at least 1500 spectra with strict criteria. This study will be carried out in accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. We are going to summarize the test performance using random effects models.Results:Based on the pooled sensitivity, specificity, and diagnostic accuracy, we intend to provide the relative diagnostic efficiency in ICC through RS.Conclusion:Through this systematic review and meta-analysis, we intend to provide the pooled sensitivity, specificity and diagnostic accuracy of RS in the diagnosis of suspected ICC. Other parameters like positive likelihood ratios (LR), negative LR, diagnostic odds ratio (DOR), and area under curve (AUC) of the summary receiver operating characteristics (SROC) curve will also be calculated and related figures will be drawn to help illustrate the efficacy of RS in the diagnosis of ICC.  相似文献   
2.
《Clinical neurophysiology》2021,132(9):2003-2011
ObjectiveA large N20 and P25 of the median nerve somatosensory evoked potential (SEP) predicts short survival in amyotrophic lateral sclerosis (ALS). We investigated whether high frequency oscillations (HFOs) over N20 are enlarged and associated with survival in ALS.MethodsA total of 145 patients with ALS and 57 healthy subjects were studied. We recorded the median nerve SEP and measured the onset-to-peak amplitude of N20 (N20o-p), and peak-to-peak amplitude between N20 and P25 (N20p-P25p). We obtained early and late HFO potentials by filtering SEP between 500 and 1 kHz, and measured the peak-to-peak amplitude. We followed up patients until endpoints (death or tracheostomy) and analyzed the relationship between SEP or HFO amplitudes and survival using a Cox analysis.ResultsPatients showed larger N20o-p, N20p-P25p, and early and late HFO amplitudes than the control values. N20p-P25p was associated with survival periods (p = 0.0004), while early and late HFO amplitudes showed no significant association with survival (p = 0.4307, and p = 0.6858, respectively).ConclusionsThe HFO amplitude in ALS is increased, but does not predict survival.SignificanceThe enlarged HFOs in ALS might be a compensatory phenomenon to the hyperexcitability of the sensory cortex pyramidal neurons.  相似文献   
3.
目的:探讨温针灸对功能性便秘(FC)患者临床症状及焦虑抑郁的改善作用。方法:选取2017年1月至2017年12月中国中医科学院广安门医院南区收治的FC患者70例作为研究对象,随机分为观察组和对照组,每组35例。对照组采用常规针刺治疗,观察组采用温针灸治疗,比较治疗前后2组患者便秘临床症状积分、首次排便时间、中医证候评分、焦虑自评量表(SAS)、抑郁自评量表(SDS)评分。结果:观察组有效率96. 00%,对照组有效率68. 00%,差异有统计学意义(P0. 05)。治疗后2组患者的周排便次数、粪便性状积分和排便困难程度均改善,中医证候评分、SAS和SDS评分下降,较治疗前差异有统计学意义(P 0. 05)。治疗后,观察组患者的周排便次数、粪便性状积分高于对照组,中医证候评分、SDS和SAS评分、首次排便时间以及排便困难程度积分小于对照组,差异有统计学意义(P 0. 05)。结论:温针灸治疗能调节胃肠道运动、润湿肠道、显著改善便秘等临床症状,对FC患者有显著临床效果。  相似文献   
4.
ObjectivesTo determine the prevalence of restless legs syndrome (RLS) and RLS-mimic conditions, the risk factors for RLS, and whether RLS contributes to functional impairment in children and adolescents with attention-deficit/hyperactivity disorder (ADHD).MethodsADHD children and adolescents were prospectively studied at the outpatient psychiatric clinic. A trained registered nurse used the 2012 Revised International Restless Legs Syndrome Study Group diagnostic criteria to diagnose RLS. Sociodemographic data and medical records were reviewed. Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P) Thai version was used to identify association between RLS and 6 domains of function [family, school (learning), school (behavior), life skills, child self-concept, social activities, and risky activities].ResultsA total of 217 patients were included. Of those, 23 (11%) patients met the criteria for RLS, and 49 (23%) had RLS-mimic conditions. Those conditions included myalgia (30/49), habitual foot tapping (23/49), positional discomfort (20/49), leg ulcer/bruise (1/49), and arthralgia/arthritis (1/49). Binary logistic regression revealed first-degree relative having RLS symptom to be significantly associated with RLS in study patients (OR: 5.06, p < 0.01). Multivariate linear regression showed RLS to be independently associated with school (behavior) (Β = 1.18, p = 0.05) and life skills (Β = 2.36, p = 0.05) impairment.ConclusionsRLS was found to be common in ADHD children and adolescents. RLS-mimic conditions were found in two-thirds of patients who previously met 4 essential RLS criteria. First-degree relative with RLS symptom was associated with RLS, and RLS was associated with functional impairment in the life skills and school (behavior) domains.  相似文献   
5.

Objectives

Despite evidence for increased musculoskeletal injury after concussion recovery, there is a lack of dynamic balance assessments that could inform management and research into this increased injury risk post-concussion. Our purpose was to identify tandem gait dynamic balance deficits in recreational athletes with a concussion history within the past 18-months compared to matched controls.

Design

Cross-sectional, laboratory study.

Methods

Fifteen participants with a concussion history (age: 19.7 ± 0.9 years; 9 females; median time since concussion 126 days, range 28–432 days), and 15 matched controls (19.7 ± 1.6 years; 9 females) with no recent concussion history participated. We measured center-of-pressure (COP) outcomes (velocity, path length, speed, dual-task cost) under 4 tandem gait conditions: (1) tandem gait, (2) tandem gait, eyes closed, (3) tandem gait, eyes open, cognitive distraction, and (4) tandem gait, eyes closed, cognitive distraction.

Results

The concussion history group demonstrated slower tandem gait velocity compared to the control group (4.0 cm/s difference), thus velocity was used as a covariate when analyzing COP path length and speed. The concussion history group (23.5%) demonstrated greater COP speed dual-task cost than the control group (16.3%) during the eyes closed dual-task condition. No other comparisons were statistically significant.

Conclusions

There may be subtle dynamic balance differences during tandem gait that are detectable after return-to-activity following concussion, but the clinical significance of these findings is unclear. Longitudinal investigations should identify acute movement deficits in varying visual and cognitive scenarios after concussion in comparison with recovery on traditional concussion assessment tools while also recording musculoskeletal injury outcomes.  相似文献   
6.
7.
近红外脑功能成像技术是近几年发展起来用于动态检测脑功能的方法,能够很好地反映抑郁人群认知活动期间大脑有氧代谢的变化,为阈下抑郁研究提供了一个新思路。本研究通过文献综述,结合中医情志理论,在过往研究的基础上基于近红外脑功能成像技术探讨中医情志刺激对阈下抑郁的反应机制,为后期研究提供理论与实践可行性的依据。  相似文献   
8.
目的 探讨台州市功能性消化不良的流行病学现状及影响因素。方法 回顾性选取2020年1月至2022年2月浙江省台州医院收治的功能性消化不良患者200例,统计患者的一般资料,分析该病的流行病学现状,对功能性消化不良的影响因素进行单因素分析,然后将差异有统计学意义的因素再进一步纳入多因素Logistic回归分析。结果 200例功能性消化不良患者中,女性发病率高于男性;30~60岁年龄段群体,患病率最高;存在暴饮暴食、喜食烫食、挑食、多食酸制品、未准时进食、常食宵夜、睡眠时间<6h、有药物过敏史、有功能性消化不良家族史、存在便秘情况者的患病率均高于未存在以上情况者,差异均有统计学意义(P<0.05)。多因素Logistic回归分析显示,性别、年龄、暴饮暴食、喜食烫食、挑食、多食酸制品、未准时进食、宵夜摄取情况、每天睡眠时间、药物过敏史、家族史、便秘是该病患病率升高的主要影响因素。结论 性别、年龄、暴饮暴食、喜食烫食、挑食、酸制品、未准时进食情况、宵夜摄取情况、每天睡眠时间、药物过敏史、家族史、便秘是功能性消化不良的主要影响因素。  相似文献   
9.
《Brain stimulation》2021,14(1):161-169
BackgroundThe prediction violation account of automatic or pre-attentive change detection assumed that the inferior frontal cortex (IFC) is involved in establishing a prediction model for detecting unexpected changes. Evidence supporting the IFC’s contribution to prediction model is mainly based on the Mismatch Negativity (MMN) to deviants violating predictions that are established based on the frequently presented standard events. However, deviant detection involves processes, such as events comparison, other than prediction model establishment.ObjectiveThe current study investigated the critical role of the IFC in establishing a prediction model during standards processing for subsequent deviant detection.MethodsTranscranial Magnetic Stimulation (TMS) was applied at the IFC to disrupt the processing of the initial 2 or 5 standards of a 3-, 6-, or 9-standard train, while the MMN responses to pitch deviant presented after the standard trains were recorded and compared.ResultsAn abolishment of MMN was only observed when TMS was delivered to the IFC at the initial 2 standards of the 3-standard train, but not at the initial 5 standards, or when TMS at the vertex or TMS sound recording was applied. The MMNs were also preserved when IFC TMS, vertex TMS, or TMS sound recording was applied at the initial 2 or 5 standards of longer trains.ConclusionThe IFC plays a critical role in processing the initial standards of a short standard train for subsequent deviant detection. This result is consistent with the prediction violation account that the IFC is important for establishing the prediction model.  相似文献   
10.
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