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   15889篇
  免费   948篇
  国内免费   449篇
耳鼻咽喉   283篇
儿科学   305篇
妇产科学   120篇
基础医学   1522篇
口腔科学   557篇
临床医学   1789篇
内科学   1492篇
皮肤病学   27篇
神经病学   2521篇
特种医学   812篇
外科学   2662篇
综合类   1680篇
预防医学   575篇
眼科学   1312篇
药学   759篇
  10篇
中国医学   592篇
肿瘤学   268篇
  2024年   39篇
  2023年   243篇
  2022年   592篇
  2021年   753篇
  2020年   719篇
  2019年   586篇
  2018年   662篇
  2017年   612篇
  2016年   567篇
  2015年   572篇
  2014年   1161篇
  2013年   1328篇
  2012年   948篇
  2011年   1090篇
  2010年   805篇
  2009年   811篇
  2008年   796篇
  2007年   709篇
  2006年   639篇
  2005年   529篇
  2004年   435篇
  2003年   341篇
  2002年   266篇
  2001年   235篇
  2000年   200篇
  1999年   217篇
  1998年   175篇
  1997年   130篇
  1996年   118篇
  1995年   100篇
  1994年   80篇
  1993年   74篇
  1992年   69篇
  1991年   58篇
  1990年   49篇
  1989年   57篇
  1988年   44篇
  1987年   34篇
  1986年   33篇
  1985年   52篇
  1984年   64篇
  1983年   63篇
  1982年   58篇
  1981年   36篇
  1980年   26篇
  1979年   20篇
  1978年   36篇
  1977年   13篇
  1976年   16篇
  1975年   8篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
《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   
2.
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   
3.
4.
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   
5.
《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   
6.
目的:对比不同矫治器对错[牙合]畸形患者面高度及前后牙咬合关系的影响。方法:选取于笔者医院接受矫治的83例错[牙合]畸形患者,根据患者矫治器类型分为直丝弓组和Begg组,分别为42例和41例。比较并分析两组患者治疗前后牙咬合关系、硬组织、磨牙及面高度的变化情况。结果:矫治后,两组患者OJ-PPV、OB-PP、LMA-MPV、LMA-MPV均降低,Begg矫治组OJ-PPV水平显著高于直丝弓矫治组,OB-PP、LMA-MPV、LMA-MPV水平显著低于直丝弓矫治组,差异均具有统计学意义(P<0.05);两组患者LAFH、LAFH/TAFH、PFH/TAFH水平均升高,其中Begg矫治组患者LAFH水平显著低于直丝弓矫治组,差异均具有统计学意义(P<0.05);两组患者LMA-MP、LMC-MP水平均升高,差异具有统计学意义(P<0.05);矫治前后,两组患者SNA、SNA、ANB水平均无统计学差异(P>0.05)。结论:两种矫治器对错[牙合]畸形患者硬组织变化均无明显影响,其中Begg矫治对患者前后牙咬合关系改善作用更强,直丝弓对患者面高度的改善能力更强。  相似文献   
7.
8.
9.

Background

Acute stroke codes may be activated for anisocoria, but how often these codes lead to a final stroke diagnosis or alteplase treatment is unknown. The purpose of this study was to assess the frequency of anisocoria in stroke codes that ultimately resulted in alteplase administration.

Methods

We retrospectively assessed consecutive alteplase-treated patients from a prospectively-collected stroke registry between February 2015 and July 2018. Based on the stroke code exam, patients were categorized as having isolated anisocoria [A+(only)], anisocoria with other findings [A+(other)], or no anisocoria [A?]. Baseline demographics, stroke severity, alteplase time metrics, and outcomes were also collected.

Results

Ninety-six patients received alteplase during the study period. Of the 94 who met inclusion criteria, there were 0 cases of A+(only). There were 9 cases of A+(other) (9.6%). A+(other) exhibited higher baseline National Institutes of Health (NIH) Stroke Scale scores compared to A? (17 versus 7; P?=?.0003), and no additional differences in demographics or alteplase time metrics. Final stroke diagnosis and other outcome measures were no different between A+(other) and A?. Of the A+ patients without pre-existing anisocoria, 5 of 6 (83%) had posterior circulation events or diffuse subarachnoid hemorrhage.

Conclusions

In this exploratory analysis, zero patients with isolated anisocoria received alteplase treatment. Anisocoria as a part of the neurologic presentation occurred in 10% of alteplase patients, and was strongly associated with a posterior circulation event. Therefore, we conclude that anisocoria has a higher likelihood of leading to alteplase treatment when identified in the presence of other neurologic deficits.  相似文献   
10.
ObjectiveTo evaluate the relationship between neural (re)organization of the somatosensory cortex and impairment of sensory function (2-point discrimination [2PD]) in individuals with unilateral cerebral palsy.MethodsWe included 21 individuals with unilateral cerebral palsy. 2PD thresholds were evaluated on thumb pads, and activation of the somatosensory cortex was recorded by functional MRI (fMRI) during passive movements of the affected hand. A lateralization index (LI) was calculated for the primary sensory (S1) and secondary sensory (S2) cortices and the correlation between the LI and 2PD thresholds was analysed.ResultsWe found a significant negative correlation between the 2PD thresholds and the S2 LI (r = −0.5, one-tailed P-value = 0.01) and a trend towards a negative correlation with the S1 LI (r = −0.4, one-tailed P-value = 0.05).ConclusionHigh levels of activation in the contralesional hemisphere were associated with high levels of sensory impairment in individuals with unilateral cerebral palsy. The interhemispheric (re)organization of the somatosensory system may not effectively compensate for somatosensory impairment.  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