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   2709381篇
  免费   179088篇
  国内免费   6774篇
耳鼻咽喉   37250篇
儿科学   90012篇
妇产科学   74599篇
基础医学   378797篇
口腔科学   73986篇
临床医学   244705篇
内科学   529919篇
皮肤病学   62836篇
神经病学   219027篇
特种医学   104078篇
外国民族医学   1050篇
外科学   404797篇
综合类   55764篇
现状与发展   5篇
一般理论   980篇
预防医学   206604篇
眼科学   60902篇
药学   197937篇
  69篇
中国医学   5460篇
肿瘤学   146466篇
  2019年   21552篇
  2018年   29428篇
  2017年   22466篇
  2016年   25944篇
  2015年   28943篇
  2014年   40100篇
  2013年   60454篇
  2012年   81117篇
  2011年   85665篇
  2010年   51677篇
  2009年   49344篇
  2008年   80479篇
  2007年   85660篇
  2006年   86726篇
  2005年   83466篇
  2004年   80983篇
  2003年   77962篇
  2002年   75594篇
  2001年   129120篇
  2000年   132674篇
  1999年   112510篇
  1998年   32087篇
  1997年   28592篇
  1996年   28919篇
  1995年   27847篇
  1994年   25736篇
  1993年   24124篇
  1992年   88043篇
  1991年   85158篇
  1990年   82588篇
  1989年   79822篇
  1988年   73096篇
  1987年   71864篇
  1986年   67373篇
  1985年   64268篇
  1984年   47925篇
  1983年   40547篇
  1982年   24006篇
  1981年   21504篇
  1979年   42692篇
  1978年   29960篇
  1977年   25564篇
  1976年   23728篇
  1975年   25274篇
  1974年   29851篇
  1973年   28499篇
  1972年   26653篇
  1971年   24494篇
  1970年   22881篇
  1969年   21539篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Detailed contemporary knowledge of the characteristics of the surgical population, national anaesthetic workload, anaesthetic techniques and behaviours are essential to monitor productivity, inform policy and direct research themes. Every 3–4 years, the Royal College of Anaesthetists, as part of its National Audit Projects (NAP), performs a snapshot activity survey in all UK hospitals delivering anaesthesia, collecting patient-level encounter data from all cases under the care of an anaesthetist. During November 2021, as part of NAP7, anaesthetists recorded details of all cases undertaken over 4 days at their site through an online survey capturing anonymous patient characteristics and anaesthetic details. Of 416 hospital sites invited to participate, 352 (85%) completed the activity survey. From these, 24,177 reports were returned, of which 24,172 (99%) were included in the final dataset. The work patterns by day of the week, time of day and surgical specialty were similar to previous NAP activity surveys. However, in non-obstetric patients, between NAP5 (2013) and NAP7 (2021) activity surveys, the estimated median age of patients increased by 2.3 years from median (IQR) of 50.5 (28.4–69.1) to 52.8 (32.1–69.2) years. The median (IQR) BMI increased from 24.9 (21.5–29.5) to 26.7 (22.3–31.7) kg.m–2. The proportion of patients who scored as ASA physical status 1 decreased from 37% in NAP5 to 24% in NAP7. The use of total intravenous anaesthesia increased from 8% of general anaesthesia cases to 26% between NAP5 and NAP7. Some changes may reflect the impact of the COVID-19 pandemic on the anaesthetic population, though patients with confirmed COVID-19 accounted for only 149 (1%) cases. These data show a rising burden of age, obesity and comorbidity in patients requiring anaesthesia care, likely to impact UK peri-operative services significantly.  相似文献   
2.

Aims

Concomitant chemoradiation is the standard of care in patients with inoperable non-small cell lung cancer. The purpose of this study was to analyse the survival outcome and toxicity data of using hypofractionated chemoradiation.

Materials and methods

One hundred patients were treated from June 2011 to November 2016. Treatment consisted of 55 Gy in 20 daily fractions concurrently with split-dose cisplatin vinorelbine chemotherapy over 4 weeks followed by two cycles of cisplatin vinorelbine only. Survival was estimated using Kaplan–Meier and Cox regression was carried out for known prognostic factors. A systematic search of literature was conducted using Medline, Embase and Cochrane databases and relevant references included.

Results

In total, 97% of patients completed radiotherapy and 73% of patients completed all four cycles of chemotherapy. One patient died of a cardiac event during consolidative chemotherapy. There were two cases of grade 4 toxicities (one sepsis, one renal impairment). Grade 3 toxicities included nausea/vomiting (17%), oesophagitis (15%), infection with neutropenia (12%) and pneumonitis (4%). Clinical benefit was seen in 86%. Two-year progression-free survival and overall survival rates were 49% and 58%, respectively. The median progression-free survival and overall survival were 23.4 and 43.4 months, respectively. The only significant prognostic factor was the number of chemotherapy cycles received (P = 0.02). The systematic review identified 13 relevant studies; a variety of regimens were assessed with variable reporting of outcomes and toxicity but with overall an improvement in survival over time.

Conclusion

Our experience compared with the original phase II trial showed improved treatment completion rates and survival with acceptable morbidity. With appropriate patient selection this regimen is an effective treatment option for locally advanced non-small cell lung cancer. This study helps to benchmark efficacy and toxicity rates while considering the addition of new agents to hypofractionated concurrent chemoradiotherapy. The agreement of a standard regimen for assessment in future trials would be beneficial.  相似文献   
3.
Abstract

Introduction: ASPIRE Excellence Awards in Student Assessment are offered to medical schools with innovative and comprehensive assessment programmes adjudged by international experts, using evidence-based criteria.

The journeys of three ASPIRE-winning medical schools toward “assessment excellence” are presented. These schools include Aga Khan University Medical College (AKU-MC), Pakistan, Southern Illinois University School of Medicine (SIUSOM), USA, and University of Leeds School of Medicine, UK.

Methods: The unfolding journeys highlighting achievements, innovations, and essential components of each assessment programme were compared to identify differences and commonalities.

Results: Cultural contextual differences included developed-versus-developing country, east-west, type of regulatory bodies, and institutional-versus-national certifying/licensing examinations, which influence curricula and assessments.

In all, 12 essential commonalities were found: alignment with institutional vision; sustained assessment leadership; stakeholder engagement; communication between curriculum and assessment; assessment-for-learning and feedback; longitudinal student profiling of outcome achievement; assessment rigor and robustness; 360° feedback from-and-to assessment; continuous enrichment through rigorous quality assurance; societal sensitivity; influencing others; and a “wow factor.”

Conclusions: Although the journeys of the three medical schools were undertaken in different cultural contexts, similar core components highlight strong foundations in student assessment. The journeys continue as assessment programmes remain dynamic and measurement science expands. This article may be helpful to other institutions pursuing excellence in assessment.  相似文献   
4.
Background: In an interprofessional training ward (ITW), students from different health professions collaboratively perform patient care with the goal of improving patient care. In the past two decades, ITWs have been established world-wide and studies have investigated their benefits. We aimed to compare ITWs with respect to their logistics, interprofessional learning outcomes and patient outcomes.

Methods: We explored PubMed, CINAHL, Web of Science and EMBASE (1990–June 2017) and included articles focusing on interprofessional, in-patient training wards with student teams of medical and other health professions students. Two independent reviewers screened studies for eligibility and extracted data.

Results: Thirty-seven articles from twelve different institutions with ITWs were included. ITWs world-wide are organized similarly with groups of 2–12 students (i.e. medical, nursing, physiotherapy, occupational therapy, and pharmacy) being involved in patient care, usually for a period of two weeks. However, the type of clinical ward and the way supervisors are trained differ.

Conclusions: ITWs show promising results in short-term student learning outcomes and patient satisfaction rates. Future ITW studies should measure students’ long-term interprofessional competencies using standardized tools. Furthermore, a research focus on the impact of ITWs on patient satisfaction and relevant patient care outcomes is important.  相似文献   

5.

Aims

The 2014 British Thyroid Association thyroid cancer guidelines recommend lifelong follow-up of thyroid cancer patients. This is probably unnecessary, can cause patient anxiety, is time consuming and places significant demand on National Health Service resources. It has been suggested that low-risk differentiated thyroid cancer (DTC) patients could be discharged to primary care once they are 5 years from diagnosis and treatment. The aim of this study was to investigate the potential safety of this practice.

Materials and methods

In total, 756 patients with dynamically risk-stratified (DRS) low-risk/excellent response to treatment DTC treated over 2001–2013 in the Leeds region were followed after diagnostic surgery and the recurrence rate calculated.

Results

The median follow-up time was nearly 10 years (5–17 years). Radiological recurrence occurred in 13/756 (1.7%) patients and was always preceded by raised thyroglobulin/ thyroglobulin antibody levels. In all 13 patients elevation of thyroglobulin occurred within 5 years of diagnosis. Two additional patients were found to have rising thyroglobulin at almost 9 and 10.5 years from diagnosis, although to date radiological recurrence has not been detected. Assuming these two patients developed recurrence with longer duration of follow-up, then 0.26% (2/756) of patients would not have their recurrence discovered within 5 years of diagnosis. To detect 100% of patients with a putative recurrence in our cohort would require 10.5 years of follow-up. Four patients had transiently raised thyroglobulin, which became undetectable within 2 years (in three patients), without any treatment and radiological recurrence was not discovered.

Conclusion

Discharge of DRS low-risk DTC patients to primary care after 5 years of secondary care follow-up is reasonable, accepting that late recurrence may occur in a very small minority of individuals (0.26%, ~1:400). A more cautious approach would be to continue monitoring for 10 years, although the frequency of assessments could be reduced with increasing duration of follow-up.  相似文献   
6.

Background

The randomized EXCEL (Evaluation of XIENCE versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) trial reported a similar rate of the 3-year composite primary endpoint of death, myocardial infarction (MI), or stroke in patients with left main coronary artery disease (LMCAD) and site-assessed low or intermediate SYNTAX scores treated with percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). Whether these results are consistent in high-risk patients with diabetes, who have fared relatively better with CABG in most prior trials, is unknown.

Objectives

In this pre-specified subgroup analysis from the EXCEL trial, the authors sought to examine the effect of diabetes in patients with LMCAD treated with PCI versus CABG.

Methods

Patients (N = 1,905) with LMCAD and site-assessed low or intermediate CAD complexity (SYNTAX scores ≤32) were randomized 1:1 to PCI with everolimus-eluting stents versus CABG, stratified by the presence of diabetes. The primary endpoint was the rate of a composite of all-cause death, stroke, or MI at 3 years. Outcomes were examined in patients with (n = 554) and without (n = 1,350) diabetes.

Results

The 3-year composite primary endpoint was significantly higher in diabetic compared with nondiabetic patients (20.0% vs. 12.9%; p < 0.001). The rate of the 3-year primary endpoint was similar after treatment with PCI and CABG in diabetic patients (20.7% vs. 19.3%, respectively; hazard ratio: 1.03; 95% confidence interval: 0.71 to 1.50; p = 0.87) and nondiabetic patients (12.9% vs. 12.9%, respectively; hazard ratio: 0.98; 95% confidence interval: 0.73 to 1.32; p = 0.89). All-cause death at 3 years occurred in 13.6% of PCI and 9.0% of CABG patients (p = 0.046), although no significant interaction was present between diabetes status and treatment for all-cause death (p = 0.22) or other endpoints, including the 3-year primary endpoint (p = 0.82) or the major secondary endpoints of death, MI, or stroke at 30 days (p = 0.61) or death, MI, stroke, or ischemia-driven revascularization at 3 years (p = 0.65).

Conclusions

In the EXCEL trial, the relative 30-day and 3-year outcomes of PCI with everolimus-eluting stents versus CABG were consistent in diabetic and nondiabetic patients with LMCAD and site-assessed low or intermediate SYNTAX scores.(Evaluation of XIENCE versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization [EXCEL]; NCT01205776)  相似文献   
7.
Our knowledge of the radiological spectrum of myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) is growing rapidly. An update on the radiological features of the disease, and its evolution is thus necessary. Magnetic resonance imaging (MRI) has an increasingly important role in the differential diagnosis of MOGAD particularly from aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD), and multiple sclerosis (MS). Differentiating these conditions is of prime importance because the management is different between the three inflammatory diseases, and thus could prevent further attack-related disability. Therefore, identifying the MRI features suggestive of MOGAD has diagnostic and prognostic implications. We herein review optic nerve, spinal cord and the brain MRI findings from MOGAD adult patients, and compare them to AQP4-NMOSD and MS.  相似文献   
8.

Background

Klippel-Trénaunay syndrome (KTS) is a severe vascular malformation that can lead to hypertrophic osteoarthritis. Total knee arthroplasty (TKA) performed in extremities affected with KTS is challenging given the high-risk vascular considerations and occasionally poor bone quality.

Methods

We identified 12 patients with KTS who underwent TKA between 1998 and 2017. There were 7 men, mean age 42 years, and mean follow-up was 7 years. Before arthroplasty, 2 patients (17%) had preoperative sclerotherapy. Preoperative vascular studies were done for 9 patients (75%) and included magnetic resonance imaging (n = 7), magnetic resonance angiography (n = 1), and computed tomography angiography (n = 1). A preoperative blood conservation protocol was used for all operations and included the use of tranexamic acid (TXA) in later years. Posterior-stabilized TKA was used in 10 cases and cruciate-retaining TKA was used in 2 cases.

Results

At final follow-up, 2 patients (17%) had undergone revision surgery: 1 for infection and 1 for tibial loosening with subsequent arthrofibrosis. Knee Society Scores (36-83, P < .0001) and functional scores (48-84, P = .0007) significantly increased between the preoperative and postoperative period. Likewise at last follow-up, the mean knee range of motion significantly increased (82°-104°, P = .04). Median blood loss for patients who received TXA was 200 mL compared to 275 mL in patients who did not receive TXA (P = .66). Likewise there was no difference (P = .5) in the proportion of patients who required a transfusion between those who received TXA (2/6, 33%) and those who did not (3/6, 50%).

Conclusion

In this small series, TKA can lead to significant clinical improvement for patients with KTS. Modern blood management techniques and a careful multidisciplinary care approach render TKA a reasonable option for select patients with KTS.

Level of Evidence

Level IV case series, therapeutic.  相似文献   
9.
<正>With an aging patient population and an increased burden of neurological disease, the demand for noninvasive alternatives to open neurosurgical procedures is imperative. Noninvasive or minimally invasive approaches to targeting brain regions include transcranial magnetic stimulation(TMS), transcranial direct current stimulation, temporally interfering electric fields, and focused ultrasound(FUS). Among these modalities, FUS offers a unique combination  相似文献   
10.

Background

The Parkland Grading Scale for Cholecystitis (PGS) was developed as an intraoperative grading scale to stratify gallbladder (GB) disease severity during laparoscopic cholecystectomy (LC). We aimed to prospectively validate this scale as a measure of LC outcomes.

Methods

Eleven surgeons took pictures of and prospectively graded the initial view of 317?GBs using PGS while performing LC (LIVE) between 9/2016 and 3/2017. Three independent surgeon raters retrospectively graded these saved GB images (STORED). The Intraclass Correlation Coefficient (ICC) statistic assessed rater reliability. Fisher's Exact, Jonckheere-Terpstra, or ANOVA tested association between peri-operative data and gallbladder grade.

Results

ICC between LIVE and STORED PGS grades demonstrated excellent reliability (ICC?=?0.8210). Diagnosis of acute cholecystitis, difficulty of surgery, incidence of partial and open cholecystectomy rates, pre-op WBC, length of operation, and bile leak rates all significantly increased with increasing grade.

Conclusions

PGS is a highly reliable, simple, operative based scale that can accurately predict outcomes after LC.

Table of contents summary

The Parkland Grading Scale for Cholecystitis was found to be a reliable and accurate predictor of laparoscopic cholecystectomy outcomes. Diagnosis of acute cholecystitis, surgical difficulty, incidence of partial and open cholecystectomy rates, pre-op WBC, operation length, and bile leak rates all significantly increased with increasing grade.  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