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   3048480篇
  免费   214520篇
  国内免费   5453篇
耳鼻咽喉   43228篇
儿科学   94305篇
妇产科学   78496篇
基础医学   437307篇
口腔科学   86195篇
临床医学   275898篇
内科学   589543篇
皮肤病学   63809篇
神经病学   248328篇
特种医学   117394篇
外国民族医学   1006篇
外科学   451930篇
综合类   67656篇
现状与发展   3篇
一般理论   1145篇
预防医学   243682篇
眼科学   70704篇
药学   227939篇
  76篇
中国医学   6702篇
肿瘤学   163107篇
  2019年   24526篇
  2018年   35122篇
  2017年   26525篇
  2016年   28943篇
  2015年   32500篇
  2014年   44645篇
  2013年   68108篇
  2012年   94819篇
  2011年   99605篇
  2010年   57290篇
  2009年   53418篇
  2008年   92888篇
  2007年   99302篇
  2006年   99375篇
  2005年   96142篇
  2004年   92524篇
  2003年   88637篇
  2002年   86849篇
  2001年   137105篇
  2000年   141433篇
  1999年   119247篇
  1998年   33692篇
  1997年   30316篇
  1996年   30240篇
  1995年   29089篇
  1994年   27258篇
  1993年   25379篇
  1992年   95565篇
  1991年   92831篇
  1990年   89949篇
  1989年   86906篇
  1988年   80628篇
  1987年   79196篇
  1986年   75090篇
  1985年   71348篇
  1984年   53845篇
  1983年   45778篇
  1982年   27389篇
  1981年   24391篇
  1979年   50318篇
  1978年   35387篇
  1977年   29846篇
  1976年   28178篇
  1975年   29992篇
  1974年   36674篇
  1973年   34827篇
  1972年   32726篇
  1971年   30184篇
  1970年   28583篇
  1969年   26583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.
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   

4.
Background: The use of improvizational theater (“improv”) in health professional education (“medical improv”) is an emerging field. However, optimal curricular design features and learning outcomes have not yet been systematically described.

Objective: To synthesize evidence on learning outcomes and curricular design elements of improvizational theater training in health professions education.

Methods: A literature search with keywords “Improv” and “Improvisational Theatre” was undertaken in January 2016 in Ovid MEDLINE, CINHAL, EMBASE, SCOPUS, Web of Science, and ERIC, with an accompanying gray literature search. Four authors coded and achieved consensus on themes relating to curricular design elements and learning outcomes, which were mapped onto the CanMEDS framework.

Results: Seven articles met inclusion criteria. Key curricular design features included (i) facilitators with dual clinical and theater expertise; (ii) creating a low-stakes environment; and (iii) engaging in debrief to highlight clinical relevance. Improv curricula were found to impact most CanMEDS roles, including: Medical Expert (comfort with uncertainty); Leader (team management); Scholar (feedback, self-reflection); Communicator (empathy, active listening, non-verbal communication); Collaborator (culture of trust); and Professional (resiliency and confidence). Mechanisms by which improv may promote acquisition of these professional competencies, and the utility of improv in areas such as interprofessional team development, leadership, and wellness and resiliency are discussed.  相似文献   

5.
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   

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.

Objective

The aim of the study was to present the results for patients with atherosclerotic aneurysm of the descending thoracic aorta (DTA) treated with a novel thoracic stent graft.

Methods

A single-center retrospective review of prospectively collected data was performed. We extracted demographic variables as well as atherosclerotic comorbidities and operation-related and imaging-related data from patients' medical records. We estimated technical success rate, in-hospital and 30-day mortality, and mortality at the end of follow-up as well as complication and reintervention rate in our study cohort. Follow-up computed tomography angiography was performed after 1 month and 6 months and yearly thereafter.

Results

A total of 30 patients (80% male; mean age, 73.7 ± 6.33 years) were treated with Ankura Thoracic Stent Graft (Lifetech, Shenzhen, China) for DTA aneurysm from February 2014 until June 2017. Technical success of the thoracic endovascular aortic repair (TEVAR) was 97% (29/30 patients). A surgical conduit was required in one patient; in three patients, we intentionally covered the left subclavian artery because of insufficient proximal landing zone. No aorta-related deaths were recorded during follow-up. During the early postoperative period, two patients (7%) with long DTA coverage developed paralysis or paraparesis, which immediately resolved after lumbar drainage. No renal complications requiring dialysis were observed. One patient (3%) developed postoperative pulmonary infection, whereas access site complications were 7%. Two symptomatic patients treated outside instructions for use (7%) developed early type IA endoleak and one patient (3%) developed type IB endoleak; type II endoleak was recorded in 3% of the study cohort. During the 30-day postoperative period, two patients died of non-TEVAR-related causes, one of gastrointestinal bleeding and the other of pulmonary infection. During a median follow-up of 31.7 (range, 38.4) months, two more patients also died of non-TEVAR-related causes, one of stroke from carotid artery disease and the other of motor vehicle trauma. In the rest of the cohort, no other adverse events were noted.

Conclusions

This novel endograft showed early evidence of a safe, effective, and durable endoprosthesis for the treatment of DTA aneurysms.  相似文献   
10.
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