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   3085篇
  免费   221篇
  国内免费   28篇
耳鼻咽喉   23篇
儿科学   93篇
妇产科学   79篇
基础医学   366篇
口腔科学   53篇
临床医学   271篇
内科学   757篇
皮肤病学   47篇
神经病学   484篇
特种医学   71篇
外科学   221篇
综合类   7篇
预防医学   281篇
眼科学   27篇
药学   300篇
中国医学   6篇
肿瘤学   248篇
  2024年   7篇
  2023年   50篇
  2022年   100篇
  2021年   149篇
  2020年   73篇
  2019年   98篇
  2018年   110篇
  2017年   92篇
  2016年   108篇
  2015年   126篇
  2014年   144篇
  2013年   172篇
  2012年   275篇
  2011年   265篇
  2010年   112篇
  2009年   124篇
  2008年   203篇
  2007年   212篇
  2006年   173篇
  2005年   176篇
  2004年   118篇
  2003年   127篇
  2002年   119篇
  2001年   18篇
  2000年   7篇
  1999年   22篇
  1998年   17篇
  1997年   15篇
  1996年   15篇
  1995年   12篇
  1994年   7篇
  1993年   8篇
  1992年   9篇
  1991年   6篇
  1990年   4篇
  1987年   5篇
  1986年   2篇
  1985年   6篇
  1984年   3篇
  1983年   5篇
  1982年   4篇
  1980年   3篇
  1979年   4篇
  1978年   2篇
  1977年   3篇
  1976年   4篇
  1973年   5篇
  1971年   3篇
  1967年   3篇
  1960年   1篇
排序方式: 共有3334条查询结果,搜索用时 18 毫秒
91.
BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is associated with an increased risk of sudden cardiac death (SCD). Risk stratification of ARVC/D patients, however, remains an unresolved issue. In this study we investigated whether heart rate variability (HRV) can be helpful in identifying ARVC/D patients with increased risk of arrhythmic events. METHODS AND RESULts: We studied 30 consecutive patients (17 males; 45.4 ± 18 years) with ARVC/D, diagnosed according to guideline criteria; 15 patients (50%) had received an implantable cardioverter defibrillator (ICD) for primary SCD prevention. HRV was assessed on 24-h ECG Holter monitoring. The primary endpoint was the occurrence of major arrhythmic events (SCD, sustained ventricular tachycardia (VT), ICD therapy for sustained VT or ventricular fibrillation (VF)). During the follow-up period (19 ± 7 months), no deaths occurred, but 5 patients (17%) experienced arrhythmic events (4 VTs and 1 VF, all in the ICD group). All HRV parameters were significantly lower in patients with, compared with those without, arrhythmic events. Low-frequency amplitude was the most significant HRV variable associated with arrhythmic events in univariate Cox regression analysis (P=0.017), and was the only significant predictor of arrhythmic events in multivariable regression analysis (hazard ratio 0.88, P=0.047), together with unexplained syncope (hazard ratio 16.1, P=0.039). CONCLUSIONS: Our data show that among ARVC/D patients HRV analysis might be helpful in identifying those with increased risk of major arrhythmic events.  相似文献   
92.
93.

Introduction and hypothesis

Since the first reported laparoscopic sacrocolpopexy in 1991, a limited number of single-center studies have attempted to assess the procedure’s effectiveness and safety. Therefore, we analyzed a national Medicare database to compare real-world short-term outcomes of open and laparoscopically assisted (including robotic) sacrocolpopexy in a United States sample of patients.

Methods

Public Use File data for a 5 % random national sample of all Medicare beneficiaries aged 65 and older were obtained from the Centers for Medicare and Medicaid Services for the years 2004–2008. Women with pelvic organ prolapse were identified using ICD-9 diagnosis codes. CPT-4 procedure codes were used to identify women who underwent open (code 57280) or laparoscopic (code 57425) sacrocolpopexy. Individual subjects were followed for 1 year post-operatively. Outcomes measured, using ICD-9 and CPT-4 codes, included medical and surgical complications and re-operation rates.

Results

Seven hundred and ninety-four women underwent open and 176 underwent laparoscopic (including robotic) sacrocolpopexy. Laparoscopic sacrocolpopexy was associated with a significantly increased rate of re-operation for anterior vaginal wall prolapse (3.4 % vs 1.0 %, p?=?0.018). However, more medical (primarily cardiopulmonary) complications occurred post-operatively in the open group (31.5 % vs 22.7 %, p?=?0.023). When sacrocolpopexy was performed with concomitant hysterectomy, mesh-related complications were significantly higher in the laparoscopic group (5.4 % vs 0 %, p?=?0.026).

Conclusion

Laparoscopic sacrocolpopexy resulted in an increased rate of reoperation for prolapse in the anterior compartment. When hysterectomy was performed at the time of sacrocolpopexy, the laparoscopic approach was associated with an increased risk of mesh-related complications.  相似文献   
94.

Background

Standard oncologic liver resections performed on elderly patients (≥70 years old) have been shown to be safe and effective. The aim of this study was to analyze operative and oncologic short-term outcomes of totally laparoscopic liver resections (TLLR) performed on elderly patients for malignancies.

Methods

We performed a retrospective statistical analysis of prospectively recorded data of TLLR performed from October 2008 to February 2012 by a single hepato-pancreato-biliary (HPB) surgeon. Patients were divided into two groups according to age (<70 vs. ≥70 years old) and perioperative outcomes were compared.

Result

A total of 60 TLLR for malignancies were identified of which 25 patients (42 %) were aged ≥70 years (Group A) and 35 (58 %) were aged <70 years (Group B). There was no difference in operative time (170 vs. 180 min, p = 0.267), median blood loss (200 vs. 250 ml, p = 0.183), number and time of Pringle maneuver (p = 0.563 and p = 0.180), blood transfusion rate (4 vs. 17 %, p = 0.222), conversion rate (4 vs. 9 %, p = 0.443), morbidity rate (12 vs. 20 %, p = 0.797), and perioperative mortality rate (0 vs. 3 %, p = 0.688). An R0 resection was achieved in 92 (Group A) versus 83 % (Group B) (p = 0.265). At a median follow-up of 18 months, 12 % of patients in Group A experienced a disease recurrence with a related mortality rate similar to that of Group B (8 vs. 12 %, p = 0.375).

Conclusion

This retrospective comparative study shows that TLLR performed on elderly for liver neoplasm are feasible and safe and lead to short-term outcomes similar to those of younger patients.  相似文献   
95.

Background

Adverse reaction to metal debris is a relatively recently described and often a silent complication of metal-on-metal (MOM) total hip replacements (THR). The Norfolk & Norwich University Hospital has been performing metal artefact reduction (MARS) MRI for 8 years in a variety of different types of MOM THR.

Questions/purposes

The aims of this review are to describe the experience of using MARS MRI in Norwich and to compare our experience with that published by other groups.

Methods

A MEDLINE keyword search was performed for studies including MRI in MOM THR. Relevant publications were reviewed and compared with published data from the Norfolk & Norwich University Hospital. The similarities and differences between these data were compared and possible explanations for these discussed.

Results

MARS MRI appears to be the most useful tool for diagnosing, staging and monitoring adverse reactions to metal debris (ARMD). There appears to be no clinically useful association between clinical and serological markers of disease and the severity of MR findings. Although severe early ARMD is associated with significant morbidity, mild disease is often stable for years. If patients with normal initial MR examinations develop ARMD, this usually occurs 7 years. A 1-year interval between MRI examinations is reasonable in asymptomatic patients.

Conclusions

There is a general international consensus that ARMD is prevalent in symptomatic and asymptomatic patients with MOM THR and that while appearances vary with the type of prosthesis, there are characteristic features that make MARS MRI essential for diagnosis, staging and surveillance of the disease.  相似文献   
96.
We did a prospective study to compare the results of treatment of subcapital fractures of the fifth metacarpal bone by closed reduction and splinting or by functional treatment. Twenty-nine consecutive patients were randomly divided into the two treatment groups (functional n = 14, and reposition and splinting n = 15). The results of treatment were satisfactory in both groups. Functionally treated patients recovered their grip force and range of movement of the affected hand a little sooner. All fractures in both groups had united within three months. There were no complications. We conclude that subcapital fractures of the fifth metacarpal bone can successfully be treated without closed reduction and splinting.  相似文献   
97.

Background

Ankylosing spondylitis (AS) is a chronic inflammatory disease with multiple articular and para-articular involvement that has a predilection for the axial skeleton. In spite of its high prevalence, ankylosis secondary to AS is a rare condition.

Case report

A 31-year-old male diagnosed with AS was referred for computed tomography (CT) of the temporomandibular joint (TMJ) due to severe mouth opening limitation. The patient had a 16-year medical history of AS and sought assistance due to TMJ pain and incapacity to open his mouth.

Results

Previous bony scintigraphy revealed involvement of the spine, sacroiliac joints, right knee, and left TMJ. Magnetic resonance imaging revealed erosion of the left condyle and posterior slope of the articular eminence, and a mass of heterogeneous signal intensity between these structures. The left condyle also presented sclerosis/edema of the bone marrow and the disk could not be identified. Sagittal and coronal CT images showed moderate alterations of the TMJ on the right side. On the left side, the images displayed markedly eroded condyle and mandibular fossa, and a bony mass resulting in ankylosis of the osseous components of the joint.

Conclusion

TMJ ankylosis in AS patients is rare and very few reports have presented imaging features of the condition through advanced diagnostic techniques.  相似文献   
98.
Adverse childhood events (ACE’s) have been empirically related to a wide range of negative health and mental health outcomes. However, not all individuals who experience ACE’s follow a trajectory of poor outcomes, and not all individuals perceive the impact of ACE’s as necessarily negative. The purpose of this study was to investigate positive and negative affect as predictors of adults’ ratings of both the childhood and adult impact of their childhood adversity. Self-report data on ACE experiences, including number, severity, and ‘impact’ were collected from 158 community members recruited on the basis of having adverse childhood experiences. Results indicated that, regardless of event severity and number of different types of adverse events experienced, high levels of negative affect were the strongest predictor of whether the adult impact of the adverse childhood events was rated as negative. All individuals rated the childhood impact of events the same. Implications are discussed.  相似文献   
99.
The study compared health-related quality of life in 165 patients with major depression and 165 randomly selected and with age- and gender-matched controls from a population sample. Health-related quality of life was measured with the self-report questionnaire (RAND-36), which consists of eight dimensions. Overall, perceived quality of life was broadly reduced among depressive outpatients, and as compared with the control group, significant impairment was observed for all eight dimensions of health-related quality of life. Accompanying somatic diseases causing disability had no additional impact on the reduction of quality of life in depressive patients. Depression per se impairs an individual's functioning ability in a number of ways. It has a significant effect not only on mental well-being but also on perceived physical functioning and bodily pain, and even on general health perceptions. Major depression seems to explain the broad decline in the quality of life among depressive patients.  相似文献   
100.
The aim of this study was to compare data on design and fabrication methods of removable partial dentures (RPDs) in two major cities in Greece. A questionnaire was sent to 150 randomly selected dental technicians. The participation rate was 79.3%. The anterior palatal strap, the lingual bar, and the Roach-type clasp arm designs were preferred. Half of the RPDs fabricated were retained using precision attachments. Differences between the two cities were observed in types of major maxillary connectors used, types of attachments and impression materials used, as well as the design of distal-extension RPDs. Postdoctoral education was found to have an impact on RPD fabrication. Despite the differences observed, design and fabrication of RPDs followed commonly used principles.  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