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   3269793篇
  免费   223405篇
  国内免费   8119篇
耳鼻咽喉   44899篇
儿科学   106631篇
妇产科学   89630篇
基础医学   456447篇
口腔科学   92200篇
临床医学   300962篇
内科学   631447篇
皮肤病学   74621篇
神经病学   267805篇
特种医学   124136篇
外国民族医学   1087篇
外科学   484076篇
综合类   74301篇
现状与发展   7篇
一般理论   1286篇
预防医学   261001篇
眼科学   74281篇
药学   236571篇
  89篇
中国医学   6658篇
肿瘤学   173182篇
  2019年   26575篇
  2018年   35926篇
  2017年   27390篇
  2016年   31438篇
  2015年   35178篇
  2014年   49424篇
  2013年   74635篇
  2012年   99354篇
  2011年   105472篇
  2010年   63525篇
  2009年   60247篇
  2008年   98270篇
  2007年   104489篇
  2006年   105627篇
  2005年   102207篇
  2004年   98179篇
  2003年   94300篇
  2002年   91281篇
  2001年   152193篇
  2000年   156217篇
  1999年   131646篇
  1998年   38731篇
  1997年   34406篇
  1996年   34620篇
  1995年   33513篇
  1994年   30759篇
  1993年   28917篇
  1992年   103429篇
  1991年   100025篇
  1990年   96955篇
  1989年   93376篇
  1988年   85785篇
  1987年   84081篇
  1986年   79440篇
  1985年   76090篇
  1984年   57231篇
  1983年   48740篇
  1982年   29363篇
  1981年   26106篇
  1979年   51804篇
  1978年   36765篇
  1977年   31065篇
  1976年   29031篇
  1975年   30652篇
  1974年   36884篇
  1973年   35343篇
  1972年   33182篇
  1971年   30802篇
  1970年   28637篇
  1969年   27037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.
5.
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   

6.
Background: Weight loss is frequently observed in pancreatic cancer patients. We aimed to study the prognostic impacts of weight loss early during chemotherapy.

Methods: A total of 72 patients of Chinese ethnicity with unresectable pancreatic cancer who underwent chemotherapy were reviewed. Critical weight loss (CWL) was defined as weight loss ≥ 5% within one month after treatment. The prognostic impact of weight loss and CWL were analyzed.

Results: 47 patients (65.3%) had weight loss after one month of treatment, with 14 (19.4%) suffering from CWL. Baseline characteristics were similar between patients with and without CWL. The median OS and Time-to-treatment-failure (TTF) of patients with CWL were shorter than those without CWL (OS: 4.8?months [CWL] versus [vs.] OS 7.1?months [No CWL]; TTF 1.6?months [CWL] vs. 3.2?months [No CWL]; both P?<?0.01). CWL was an independent adverse prognosticator for OS (Hazard Ratio [HR]?=?2.50; P?=?0.01) and TTF (HR = 2.71; P?<?0.01). Other independent prognosticators for OS were serum albumin <35?mg/dl and CA19-9?≥?1000?IU/ml, while CWL was the only independent prognosticator for TTF (HR 2.71 [95% CI 1.33–5.52]; P?<?0.01).

Conclusions: Development of CWL in early course of chemotherapy was associated with worse prognosis in Chinese patients with unresectable pancreatic cancers.  相似文献   

7.

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   
8.

Objective

It is useful for reviewers of economic evaluations to assess quality in a manner that is consistent and comprehensive. Checklists can allow this, but there are concerns about their reliability and how they are used in practice. We aimed to describe how checklists have been used in systematic reviews of health economic evaluations.

Methods

Meta-review with snowball sampling. We compiled a list of checklists for health economic evaluations and searched for the checklists’ use in systematic reviews from January 2010 to February 2018. We extracted data regarding checklists used, stated checklist function, subject area, number of reviewers, and issues expressed about checklists.

Results

We found 346 systematic reviews since 2010 that used checklists to assess economic evaluations. The most common checklist in use was developed in 1996 by Drummond and Jefferson, and the most common stated use of a checklist was quality assessment. Checklists and their use varied within subject areas; 223 reviews had more than one reviewer who used the checklist.

Conclusions

Use of checklists is inconsistent. Eighteen individual checklists have been used since 2010, many of which have been used in ways different from those originally intended, often without justification. Different systematic reviews in the same subject areas would benefit from using one checklist exclusively, using checklists as intended, and having 2 reviewers complete the checklist. This would increase the likelihood that results are transparent and comparable over time.  相似文献   
9.

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   
10.
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   
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