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   443476篇
  免费   30674篇
  国内免费   10505篇
耳鼻咽喉   4805篇
儿科学   11374篇
妇产科学   7241篇
基础医学   34486篇
口腔科学   10762篇
临床医学   51148篇
内科学   56711篇
皮肤病学   5153篇
神经病学   24169篇
特种医学   12907篇
外国民族医学   34篇
外科学   54344篇
综合类   69032篇
现状与发展   17篇
一般理论   33篇
预防医学   42766篇
眼科学   6465篇
药学   38757篇
  552篇
中国医学   38656篇
肿瘤学   15243篇
  2024年   1551篇
  2023年   7412篇
  2022年   13479篇
  2021年   18490篇
  2020年   17434篇
  2019年   22099篇
  2018年   19687篇
  2017年   17189篇
  2016年   14285篇
  2015年   13237篇
  2014年   27012篇
  2013年   28261篇
  2012年   23926篇
  2011年   26314篇
  2010年   21587篇
  2009年   19345篇
  2008年   18791篇
  2007年   19500篇
  2006年   17211篇
  2005年   14672篇
  2004年   12003篇
  2003年   10467篇
  2002年   8330篇
  2001年   7519篇
  2000年   6145篇
  1999年   5368篇
  1998年   4387篇
  1997年   4152篇
  1996年   3562篇
  1995年   3441篇
  1994年   3250篇
  1993年   2559篇
  1992年   2639篇
  1991年   2228篇
  1990年   1954篇
  1989年   1742篇
  1988年   1669篇
  1987年   1460篇
  1985年   4083篇
  1984年   5097篇
  1983年   3551篇
  1982年   4047篇
  1981年   3731篇
  1980年   3295篇
  1979年   3057篇
  1978年   2677篇
  1977年   1998篇
  1976年   2257篇
  1975年   1700篇
  1974年   1475篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.

Aims

Variations of the anatomy of donor hepatic arteries increase the number of arterial anastomoses during liver transplantation and, possibly, the incidence of hepatic artery thrombosis (HAT). In this study, we describe the arterial anatomic variations in liver grafts procured and transplanted by a single center in Greece, the techniques of arterial anastomosis, and their effect on the incidence of early HAT.

Materials and Methods

From January 2013 to December 2017, the arterial anatomy of 116 grafts procured for liver transplantation were recorded, as well as the technique of arterial anastomosis and the incidence of early hepatic artery thrombosis (HAT <30 days).

Results

A single hepatic artery was recorded in 72.41% of the procured grafts, an aberrant left hepatic artery (accessory or replaced) in 18 grafts (15.52%), and an aberrant right hepatic artery (accessory or replaced) in 17 grafts (14.66%), while other variations were observed in less than 1% of the procured livers. Of the 116 primary liver transplantations, 6 patients (5.17%) developed early HAT <30 days. Two of these patients (1.72%) had 1 anastomosis of the hepatic artery and 4 (3.45%) had 2 anastomoses due to anatomic variations.

Conclusions

Anatomic variations of the hepatic artery in liver grafts is a common finding and increase the incidence of early HAT but not to a degree to make these grafts unusable.  相似文献   
32.
Introduction: Recently, a new minimally invasive single bundle technique for anatomic ACL reconstruction has been described, called the ‘All-Inside graft-link technique’. One of the advantages of this procedure is the reduced morbidity at the donor site as the graft choice is the quadrupled semitendinosus, thus sparing the gracilis tendon. The aim of this study was to evaluate isokinetic flexion strength recovery in patients who underwent a gracilis sparing technique compared to those with a full-tibial tunnel technique using a doubled gracilis and semitendinosus tendons (DGST) graft.

Methods: Patients were divided into two groups: Group A (22 patients) who underwent ACL reconstruction performed with an All-Inside graft-link technique; Group B (22 patients) who underwent ACL reconstruction with an Out-In technique and DGST graft. At a mean follow-up of 13 months, quadriceps and hamstring isokinetic peak torque deficits were recorded.

Results: In group A, the mean side to side peak torque flexion difference between the operated and non-operated limbs was ?3% and the mean torque at 30° was ?7.5% at high angular velocity (180°/sec); the mean peak flexion torque was 7.2% and the mean torque at 30° was 3.1% at low angular velocity (60°/sec).

In group B, the mean side to side peak flexion torque was ?3.5% and the mean torque at 30° was ?7.6% at high angular velocity (180°/sec); the mean peak flexion torque was ?7.2% and the mean torque at 30° was ?11% at low angular velocity (60°/sec).

A statistically significant difference was found between the two groups at lower angular velocity both for the mean peak flexion torque and the mean torque at 30° (= 0.009), with better results in the study group.

Discussion/conclusion: Gracilis sparing technique is a minimally invasive technique for ACL reconstruction and yielded a significantly better flexion strength recovery at lower angular velocity compared to a full tibial tunnel technique with DGST for ACL reconstruction.  相似文献   

33.

Objectives

The current study investigated the effects of two exercise interventions on cognitive function amongst breast cancer survivors.

Design

Pilot randomised-controlled trial.

Methods

Seventeen female cancer survivors (mean: 62.9 ± 7.8 years) were randomised into three groups: high-intensity interval training (HIIT, n = 6); moderate-intensity continuous training (MOD, n = 5); or wait-list control (CON, n = 6). The HIIT and MOD groups exercised on a cycle ergometer 3 days/week for 12-weeks. Primary outcomes were cognitive function assessments utilising CogState. Secondary outcomes were resting middle cerebral artery blood flow velocity, cerebrovascular reactivity and aerobic fitness (VO2peak). Data were analysed with General Linear Mixed Models and Cohen’s d effect sizes were calculated.

Results

All 17 participants who were randomised were available for follow-up analysis and adherence was similar for HIIT and MOD (78.7 ± 13.2% vs 79.4 ± 12.0%; p = 0.93). Although there were no significant differences in the cognitive and cerebrovascular outcomes, HIIT produced moderate to large positive effects in comparison to MOD and CON for outcomes including episodic memory, working memory, executive function, cerebral blood flow and cerebrovascular reactivity. HIIT significantly increased VO2peak by 19.3% (d = 1.28) and MOD had a non-significant 5.6% (d = 0.72) increase, compared to CON which had a 2.6% decrease.

Conclusions

This study provides preliminary evidence that HIIT may be an effective exercise intervention to improve cognitive performance, cerebrovascular function and aerobic fitness in breast cancer survivors. Considering the sample size is small, these results should be confirmed through larger clinical trials.  相似文献   
34.
Background: Before implementation of the new scale, the Swedish modified version of the Postural Assessment Scale for Stroke Patients (SwePASS), to clinical practice, it is fundamental to analyze its measurement properties.Objective: To examine the inter-rater reliability of the SwePASS in the acute phase after stroke.

Methods: Day 3 to day 7 after admission to a stroke unit, 64 persons with stroke were assessed twice, using the SwePASS, by two physiotherapists. Inter-rater reliability was determined using percentage-agreement and the rank-invariant method: relative position, relative concentration, and relative rank variance.

Results: The raters showed a percentage agreement of ≥75% in the assessments using the SwePASS. For 9 of the 12 items, the percentage agreement was >80%. For 8 of the 12 items, there was a statistically significant change in position, revealed in relative position values between 0.08 and 0.15. Three items had statistically significant positive relative concentration values between ?0.11 and 0.10. Except for a statistically significant negligible relative variance value of 0.01 for the items 1 and 8, there was no relative variance.

Conclusions: The SwePASS shows an acceptable inter-rater reliability, albeit with potential for improvement. The reliability can be improved by a consensus how to interpret the scale between the raters prior to implementation in the clinic.  相似文献   

35.
Objectives: There is a paucity of reporting on surgical outcomes of isolated posterior cruciate ligament reconstruction (PCLR). We hypothesize that isolated PCL injuries failing nonoperative treatment achieve good outcomes and are able to return to sport following PCLR.

Methods: A retrospective analysis was performed to identify patients with isolated PCL injuries that underwent reconstruction between 2001 and 2014. Patients with multi-ligamentous injury or another concomitant knee pathology were excluded. Medical records were reviewed for demographic, clinical and operative data. Patients were contacted for administration of a telephone-based questionnaire which included the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation form, Lysholm-Tegner scales, Marx activity scale (MAS), return to sport status, and patient satisfaction instruments.

Results: A total of 15 isolated PCL reconstructions in 14 patients with a mean age of 27.5 years (range 17–43) met the study inclusion criteria; mean follow up was 6.3 years (range 1.4–15.2). Pre-operatively, the primary complaint was knee instability in all patients; on physical examination, lack of a firm end point during posterior drawer testing was found in 93% (14/15) of the knees. In total, 12 of 15 knees underwent transtibial, single-bundle PCLR and three of 15 underwent tibial inlay, double bundle PCLR. Graft types included: quadriceps autograft (7/15), Achilles allograft (6/15), and hamstring autograft (2/15). There were no graft failures in our patient cohort. At most recent follow up the mean scores respectively on the IKDC form, Lysholm-Tegner scales and MAS were (standard deviation): 77.3 (16.5), 83.1 (17.9), 6.13 (2.6), and 7.1 (6.0). All fourteen patients were athletes prior to their injury and 79% (11/14) returned to sport and overall patient satisfaction was 9.2/10.

Conclusions: Isolated PCLR provides good outcomes at mean medium-term follow up with restoration of function, high rate of return to sport and overall patient satisfaction.  相似文献   

36.

Background

Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.

Methods

We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).

Results

Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.

Conclusions

Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation.  相似文献   
37.
Objective: The objective of this study was to gain greater insight into individuals’ quality of life (QOL) definitions, appraisals, and adaptations following spinal cord injury (SCI).

Design: A mixed-methods design, applying the Schwartz and Sprangers response shift (RS) model. RS is a cognitive process wherein, in response to a change in health status, individuals change internal standards, values, or conceptualization of QOL

Setting: Community-dwelling participants who receive medical treatment at a major Midwestern medical system and nearby Veterans’ Affairs hospital.

Participants: A purposive sample of participants with SCI (N?=?40) completed semi-structured interviews and accompanying quantitative measures.

Interventions: Not applicable.

Outcome Measures: Qualitative data were analyzed using content analysis to identify themes. Analysis of variance were performed to detect differences based on themes and QOL, well-being, and demographic and injury characteristics.

Results: Four RS themes were identified, capturing the range of participant perceptions of QOL. The themes ranged from complete RS, indicating active engagement in maintaining QOL, to awareness and comparisons redefining QOL, to a relative lack of RS. Average QOL ratings differed as a function of response shift themes. PROMIS Global Health, Anxiety, and Depression also differed as a function of RS themes.

Conclusion: The RS model contextualizes differences in QOL definitions, appraisals, and adaptations in a way standardized QOL measures alone do not.  相似文献   

38.
39.
40.
Introduction and objectivesThe Spanish Society of Cardiology/Spanish Heart Foundation (SEC/FEC) annually awards grants for cardiovascular research projects. Our objective was to analyze the trend in these investments and their resulting scientific production from 2007 to 2012.MethodsA search of the publications funded by the SEC/FEC was carried out, according to the following inclusion criteria: publication in a journal indexed in MEDLINE or EMBASE, publication date after the grant, authorship by the principal investigator of the grant, and acknowledgment of SEC/FEC funding. The impact factor and subsequent citations of the articles were analyzed (Web of Science).ResultsA total of 235 grants were awarded (39/y) with an allocation of €3 854 300 (€642 383/y), 37% of them to women. In all, 122 publications resulted from 88 research projects (37%) funded by the SEC/FEC. Up to October 2017, these publications had received 2258 citations in subsequent studies in the Web of Science, with a mean of 18.5 and a median of 8 citations/study.ConclusionsDespite the economic crisis, the mean number and size of the grants awarded by the SEC/FEC increased in the period analyzed. Grants were awarded on an equal opportunity basis to men and women. The bibliometric impact of the funded projects is acceptable, although efforts should be made to improve it.  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