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   2350篇
  免费   141篇
  国内免费   17篇
耳鼻咽喉   25篇
儿科学   96篇
妇产科学   38篇
基础医学   421篇
口腔科学   26篇
临床医学   296篇
内科学   458篇
皮肤病学   49篇
神经病学   231篇
特种医学   51篇
外科学   219篇
综合类   12篇
预防医学   208篇
眼科学   28篇
药学   189篇
中国医学   3篇
肿瘤学   158篇
  2023年   17篇
  2022年   19篇
  2021年   45篇
  2020年   32篇
  2019年   46篇
  2018年   69篇
  2017年   47篇
  2016年   57篇
  2015年   58篇
  2014年   90篇
  2013年   120篇
  2012年   189篇
  2011年   204篇
  2010年   109篇
  2009年   95篇
  2008年   163篇
  2007年   157篇
  2006年   150篇
  2005年   134篇
  2004年   111篇
  2003年   118篇
  2002年   95篇
  2001年   24篇
  2000年   20篇
  1999年   26篇
  1998年   30篇
  1997年   20篇
  1996年   27篇
  1995年   15篇
  1994年   13篇
  1993年   11篇
  1992年   16篇
  1991年   12篇
  1990年   11篇
  1989年   19篇
  1988年   10篇
  1987年   14篇
  1986年   10篇
  1985年   12篇
  1984年   6篇
  1982年   5篇
  1980年   7篇
  1979年   8篇
  1977年   7篇
  1976年   6篇
  1974年   4篇
  1973年   4篇
  1972年   4篇
  1971年   5篇
  1967年   5篇
排序方式: 共有2508条查询结果,搜索用时 31 毫秒
61.

Objectives

Recent animal studies have suggested a key role for cellular prion protein (PrPc) in the pathological consequences of amyloid plaque formation, the hallmark of Alzheimer's disease. This epidemiological study investigated whether serum concentrations of PrPc are associated with cognitive functioning in humans.

Design, Setting, Participants

Cross-sectional study of 1,322 participants from the elderly general population in Germany, aged 65 + years at baseline (2000–2002).

Measurements

Cognitive functioning was assessed by the COGTEL phone interview 5 years after baseline. Serum PrPc was determined by a commercial immunoassay.

Results

In multiple linear regression adjusted for important confounders, subjects in higher PrPc quintiles appeared to have lower cognitive functioning scores than those in the lowest PrPc quintile. Spline regression suggested pronounced non-linearity with an inverse association between PrPc and cognitive functioning levelling off beyond median PrPc. Cognitive subdomain-specific models produced somewhat heterogeneous results.

Conclusion

The findings are suggestive of an independent association of PrPc with cognitive functioning in humans. Confirmatory and longitudinal studies are needed to elucidate the potential of PrPc for applications in early risk stratification for cognitive impairment.  相似文献   
62.
ObjectiveThe aim of this study was to examine the temporal stability of event-related desynchronization/synchronization (ERD/S) patterns over several sessions as a function of mental task, frequency band, brain region and time interval during the imagery period.MethodsNine volunteers participated in four sessions within 2 weeks of multi-channel EEG recordings. They performed seven mental tasks (i.e. mental rotation, word association, auditory imagery, mental subtraction, spatial navigation, imagery of familiar faces, motor imagery) during 7-s imagery periods. Cronbach’s alpha coefficients were calculated over sessions to evaluate the stability of ERD/S values.ResultsThe word association, mental subtraction and spatial navigation task showed highest stability. Cronbach’s alpha coefficients were highest in the alpha bands (7–10, 10–13 Hz), poorer in the beta bands (13–20, 20–30 Hz) and poorest in the theta band (4–7 Hz). In the majority of tasks, the first time interval and posterior left regions showed highest stability and strongest ERD in the alpha and beta bands.ConclusionStability of ERD/S is strongly dependent on the specific task and differs between time intervals of the imagery period. Furthermore, stability was related to ERD in the alpha and beta bands.SignificanceThe reliability of brain activation patterns is highly relevant for brain–computer interface developments.  相似文献   
63.
64.
ObjectivesObesity is known to be an important risk factor for type 2 diabetes and its related comorbid conditions; however, its specific impact on generic health-related quality of life (HRQL) is less clear. The objective of this study was to estimate the association between body mass index (BMI) and HRQL in individuals with type 2 diabetes.MethodsThe EQ-5D quality of life questionnaire was administered in a follow-up of 10,385 participants aged 33–94 of the population-based German MONICA/KORA surveys. 1033 participants with type 2 diabetes were identified by self-report combined with validated physician diagnoses. Semiparametric additive regression models were used to estimate the effect of BMI on EQ-5D health utilities adjusted for age, sex, education and comorbidities.ResultsBMI was significantly associated with EQ-5D health utilities even after adjustment for macro- and microvascular complications. The functional relationship between BMI and utilities was nonlinear, reflecting optimal health around 26 kg/m2 and significantly decreasing health utilities with increasing levels of overweight and obesity (? 0.09 points between BMI values 26 and 40). Among the diabetic complications, the history of a stroke (? 0.13) and neuropathy (? 0.10) were the strongest predictors of reduced health utility scores.ConclusionsBMI is strongly associated with health utilities in persons with type 2 diabetes. This suggests that lifestyle measures to reduce obesity can markedly improve patients' health-related quality of life and that the negative effect of potential weight gain should be taken into account when determining patient preferences for different type 2 diabetes treatment options.  相似文献   
65.
66.

Purpose

The study aim was to evaluate patient acceptance and content with remote follow-up (FU) of their implantable cardioverter defibrillator (ICD) and to estimate patients?? wish for changes in remote follow-up routines.

Methods

Four hundred seventy-four ICD patients at the device follow-up clinic at Rigshospitalet using CareLink? (Medtronic) remote follow-up, who had made ??2 transmissions, received a questionnaire.

Results

Three hundred eighty-five patients (81.2%) answered. Mean time with ICD was 56?±?45?months and mean age was 62?±?13?years; 80% was male. Diagnosis related to ICD implant was: ischemic heart disease in 56% and dilated cardiomyopathy in 21%. Twenty-six percent had primary prophylactic indication. Mean time on remote FU was 16.4?±?6.9?months. Mean time spent on in-clinic FU (two-way transport and FU) was 4?h and 36?min?±?7?h and 50?min, excluding 12 patients from Greenland and Faroe Islands. Ninety-five percent of the patients was very content or content with remote FU compared to in-clinic FU; 3% was less content and 2% was not content. For scheduled transmissions, 21% of the patients wished for a faster reply (sms or e-mail) compared to current practice with a letter. Eighty-four percent preferred more detailed information concerning ICD leads, battery status, and ICD therapies. A total of 96 patients (25%) had performed extra unscheduled remote transmissions: 20 due to shock, 20 due to alarm, 35 due to palpitations, and 18 for other or combined reasons.

Conclusion

Ninety-five percent of the patients were content with the remote FU. Only 25% had unscheduled transmissions and most unscheduled transmissions were for appropriate reasons. Eighty-four percent of the patients wished for a more detailed response and 21% wished for a faster reply after routine transmissions.  相似文献   
67.

Background  

HIV-associated general immune activation is a strong predictor for HIV disease progression, suggesting that chronic immune activation may drive HIV pathogenesis. Consequently, immunomodulating agents may decelerate HIV disease progression.  相似文献   
68.

Introduction and hypothesis

To prospectively evaluate the use of a particular polypropylene Y mesh for robotic sacrocolpopexy.

Methods

This was a prospective study of 120 patients who underwent robotic sacrocolpopexy. We compared preoperative and 12-month postoperative objective and subjective assessments via the Pelvic Organ Prolapse Quantification (POP-Q), the Pelvic Floor Distress Inventory, Short Form 20 (PFDI-20); the Pelvic Floor Impact Questionnaire, Short Form 7 (PFIQ-7); and the Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire 12 (PISQ-12). Objective “anatomical success” was defined as POP-Q stage 0 or 1 at all postoperative intervals. We further defined “clinical cure” by simultaneously considering POP-Q points and subjective measures. To be considered a “clinical cure,” a given patient had to have all POP-Q points ≤0, apical POP-Q point C ≤5, no reported pelvic organ prolapse symptoms on the PFDI-20, and no reoperation for prolapse at all postoperative intervals.

Results

Of the 120 patients, 118 patients completed the 1-year follow-up. The objective “anatomical success” rate was 89 % and the “clinical cure” rate was 94 %. The PFDI-20 mean score improved from 100.4 at baseline to 21.0 at 12 months (p?<?0.0001); PFIQ-7 scores improved from 61.6 to 8.0 (p?<?0.0001); and PISQ-12 scores improved from 35.7 to 38.6 (p?<?0.0009). No mesh erosions or mesh-related complications occurred.

Conclusion

The use of this ultra-lightweight Y mesh for sacrocolpopexy, eliminated the mesh-related complications in the first postoperative year, and provided significant improvement in subjective and objective outcomes.  相似文献   
69.
Abstract

The aim of this study was to identify personality factors predicting psychotherapy utilization on the basis of personality pathology, affect regulation and interpersonal functioning. The authors assessed affectivity (using the Affect Experience and Affect Regulation Q-Sort), interpersonal context (using the Quality of Object Relations Scale), and character pathology (using the Shedler–Westen Assessment Procedure-200). Combination of instruments showed one stable factor predictive for nonengagement in psychotherapy, revealing an externalizing personality dimension, dominated by externalizing defenses, acting out, deficient superego functions, and impairment in reflective functioning and in relating to others. Stability of the predictive power of this personality factor for therapy engagement could be shown, and replication in two other samples confirmed the findings. The results highlight the importance of measuring affect-regulatory mechanisms, and clinical implications for intervention techniques are discussed.  相似文献   
70.
We delineated the achievement of early speech-language milestones in 15 young children with Rett syndrome (MECP2 positive) in the first two years of life using retrospective video analysis. By contrast to the commonly accepted concept that these children are normal in the pre-regression period, we found markedly atypical development of speech-language capacities, suggesting a paradigm shift in the pathogenesis of Rett syndrome and a possible approach to its early detection.  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