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   4083篇
  免费   357篇
  国内免费   7篇
耳鼻咽喉   36篇
儿科学   78篇
妇产科学   100篇
基础医学   393篇
口腔科学   76篇
临床医学   515篇
内科学   857篇
皮肤病学   43篇
神经病学   507篇
特种医学   119篇
外科学   542篇
综合类   125篇
一般理论   6篇
预防医学   430篇
眼科学   42篇
药学   308篇
中国医学   1篇
肿瘤学   269篇
  2022年   27篇
  2021年   80篇
  2020年   46篇
  2019年   69篇
  2018年   81篇
  2017年   58篇
  2016年   72篇
  2015年   69篇
  2014年   100篇
  2013年   159篇
  2012年   188篇
  2011年   214篇
  2010年   150篇
  2009年   116篇
  2008年   202篇
  2007年   212篇
  2006年   176篇
  2005年   166篇
  2004年   162篇
  2003年   186篇
  2002年   124篇
  2001年   113篇
  2000年   128篇
  1999年   117篇
  1998年   36篇
  1997年   41篇
  1996年   31篇
  1995年   30篇
  1993年   27篇
  1992年   81篇
  1991年   77篇
  1990年   59篇
  1989年   66篇
  1988年   59篇
  1987年   49篇
  1986年   49篇
  1985年   65篇
  1984年   64篇
  1983年   55篇
  1982年   45篇
  1981年   30篇
  1980年   35篇
  1979年   56篇
  1978年   52篇
  1977年   54篇
  1976年   43篇
  1975年   31篇
  1974年   36篇
  1973年   37篇
  1968年   28篇
排序方式: 共有4447条查询结果,搜索用时 15 毫秒
91.
92.
Ulcerative colitis (UC) is associated with a number of extraintestinal manifestations (EIMs) that may affect most organ systems. Among the EIMs, those involving the lung are rare. We report a case of pulmonary involvement and pyoderma gangrenosum in a patient with refractory UC. A chest computed tomography showed multiple nodular infiltrates in bilateral lungs. The patient had no respiratory symptoms. No infectious agents were detected. A transbronchial biopsy specimen showed nonspecific features. Prednisolone was initiated with significant improvement in the patient’s abdominal symptoms and pyoderma gangrenosum. Subsequent imaging after steroid therapy showed improvement of the pulmonary infiltrates. The patient’s abdominal symptoms relapsed when prednisolone was tapered. The patient subsequently received a proctocolectomy. Chest radiographs have shown resolution of pulmonary infiltrates. Because pulmonary involvement follows an independent course and a proctocolectomy may not be protective against a recurrence of pulmonary involvement, a careful follow-up should be continued.  相似文献   
93.
Kane JM  Backer CL 《Chest》2012,141(1):274-5; author reply 275
  相似文献   
94.
95.
Although concern has been raised about antipsychotic prescribing to youth with attention-deficit/hyperactivity disorder (ADHD), the available database is limited to individual studies. Therefore, in order to provide a synthesis of prevalence and time trends, we conducted a systematic review and pooled analysis of pharmaco-epidemiologic data on antipsychotic use in ADHD youth. Of 1806 hits, 21 studies (N) were retained that reported analyzable data for three separate populations: 1) antipsychotic-treated youth (N?=?15, n?=?341,586); 2) ADHD youth (N?=?9, n?=?6,192,368), and 3) general population youth (N?=?5, n?=?14,284,916). Altogether, 30.5?±?18.5 % of antipsychotic-treated youth had ADHD. In longitudinal studies, this percentage increased over time (1998–2007) from 21.7?±?7.1 % to 27.7?±?7.7 %, ratio?=?1.3?±?0.4. Furthermore, 11.5?±?17.5 % of ADHD youth received antipsychotics. In longitudinal studies, this percentage also increased (1998–2006) from 5.5?±?2.6 % to 11.4?±?6.7 %, ratio?=?2.1?±?0.6. Finally, 0.12?±?0.07 % of youth in the general population were diagnosed with ADHD and received antipsychotics. Again, in longitudinal studies, this percentage increased over time (1993–2007): 0.13?±?0.09 % to 0.44?±?0.49 %, ratio?=?3.1?±?2.2. Taken together, these data indicate that antipsychotics are used by a clinically relevant and increasing number of youth with ADHD. Reasons for and risk/benefit ratios of this practice with little evidence base require further investigation.  相似文献   
96.
Global surgery initiatives increasingly are focused on strengthening education and local health care systems to build surgical capacity. The goal of this education project was to support local health care providers in augmenting the surgical curriculum at a new medical school, thus promoting long-term local goals and involvement. Working with local surgeons, residents, and medical and assistant medical officer students, we identified the most common surgical conditions presenting to Weill Bugando Medical Centre in Mwanza, Tanzania, and the areas of greatest need in surgical education. We developed an 8-week teaching schedule for undergraduate students and an electronic database of clinical surgery topics. In addition, we started teaching basic surgical skills in the operating theatre, bridging to an official and recurring workshop through a supporting international surgery organization. The medical and assistant medical officer students reported increased satisfaction with their clinical surgery rotations and mastery of key educational subjects. The initiation of an Essential Surgical Skills workshop through the Canadian Network for International Surgery showed students had improved comfort with basic surgical techniques. Short-term surgical missions may appear to fill a void in the shortage of health care in the developing world. However, we conclude that global health resources are more appropriately used through projects giving ownership to local providers and promoting education as a foundation of development. This results in better coordination among local and visiting providers and greater impact on education and long-term growth of health care capacity.Les initiatives internationales en ce qui concerne la chirurgie sont de plus en plus axées sur le renforcement des programmes de formation et des systèmes de soins de santé locaux pour consolider les capacités dans ce domaine. L’objectif de ce projet éducatif était d’aider les professionnels de la santé locaux à enrichir le programme de chirurgie d’une nouvelle faculté de médecine et de favoriser ainsi l’atteinte des objectifs et une meilleure participation à long terme à l’échelle locale. En travaillant avec des chirurgiens, des résidents, des étudiants en médecine et de futurs aides-médecins locaux, nous avons recensé les chirurgies les plus fréquentes au Centre médical Weill Bugando à Mwanza à la Tanzanie, et les domaines de la chirurgie où les besoins de formation sont les plus grands. Nous avons mis sur pied un calendrier d’enseignement échelonné sur 8 semaines pour les étudiants et une base de données électronique sur les différents types de chirurgie clinique. Nous avons également commencé à enseigner les techniques chirurgicales de base au bloc opératoire, en parallèle avec un atelier officiel récurrent, grâce au soutien d’une association internationale de chirurgie. Les étudiants en médecine et les futurs aides-médecins se sont dits plus satisfaits de leur stage de chirurgie clinique et de leur maîtrise des principaux enjeux didactiques. Le lancement d’un atelier sur les compétences chirurgicales de base, rendu possible grâce au Réseau canadien pour la chirurgie internationale, a montré que les étudiants se sentent plus à l’aise avec les techniques chirurgicales de base. Les missions chirurgicales de courte durée peuvent sembler combler une lacune dans les pays en développement où les soins de santé sont insuffisants. Toutefois, nous concluons que les ressources en santé internationale sont utilisées de manière plus appropriée dans le cadre de projets qui responsabilisent les fournisseurs de soins locaux et favorisent leur formation comme base du développement. Cela donne lieu à une meilleure coordination entre les professionnels locaux et les coopérants et exerce un impact plus grand sur la formation et la croissance des capacités en matière de soins de santé à long terme.International volunteerism has a long-standing history among surgeons, particularly those with academic affiliations and relationships with departments of global health. With growing recognition of World Health Organization (WHO) projections that surgical diseases will represent a substantial global health burden by 2030,1 and with current data showing that 90% of deaths from injuries occur in developing countries,2 this interest in surgical volunteerism has increased steadily in recent years.3Many attempts to ameliorate the disparities in worldwide surgical care have been focused on short-term medical missions. However, these missions arguably undermine the local health care systems and disrupt relationships among physicians and their patients.4 This mode of service delivery is unsustainable, perpetuating a cycle of externally imposed and often uncoordinated “solutions” that fail to offer systematic education and infrastructural development based on local goals.In an effort to develop a sustainable global surgery relationship that will provide long-term support and engender self-reliance among local surgeons, Weill Cornell Medical College has established a relationship with the newly founded Weill Bugando University College of Health Sciences (Weill BUCHS) in Mwanza, Tanzania. Working with both Weill BUCHS and the existing Bugando Medical Centre (BMC), the project involves assisting with improving and organizing the existing surgical curriculum for undergraduate medical students, emphasizing scheduled bedside teaching, and providing training in basic surgical procedures and surgical subspecialty techniques for residents and attending surgeons in neurosurgery. It also includes the addition of the Canadian Network for International Surgery (CNIS) Essential Surgical Skills (ESS) workshop for all final-year medical students, which aims to improve student skills on a defined set of basic surgical procedures.Unlike other missions or surgical electives in which Western surgeons travel for brief periods of time to developing countries with the purpose of performing large volumes of surgical cases, the emphasis of involvement with Weill BUCHS is to assist in the training and education of physicians to create independent and sustainable medical care. Weill Cornell has worked with Weill BUCHS surgeons to provide instruction on didactic topics and basic surgical skills and to schedule recurring visits by Weill Cornell surgical faculty and residents for teaching purposes.This development of Weill BUCHS grew from recognition that Tanzania suffers from a dearth of physicians, with only 0.1 physicians per 10 000 population — one of the lowest physician:patient ratios in the world.5 In addition, the health work force in Tanzania is unevenly distributed, with only one-third of doctors practising in the rural areas where three-quarters of the population resides.  相似文献   
97.
98.
BackgroundAutonomic abnormalities have been implicated in both diastolic dysfunction and abnormal heart rate (HR) recovery; however, few studies have assessed whether diastolic dysfunction is associated with abnormal HR recovery and whether both modify exercise capacity.Methods and ResultsExercise echocardiography with diastolic assessment was performed in 2,826 patients with normal wall motion responses to symptom-limited exercise testing. HR recovery was defined as the difference in HR from peak exercise to 1 minute in recovery; abnormal HR recovery was defined as the lowest quartile. Mean HR recovery was 32 ± 14 beats per minute. Patients with diastolic dysfunction or abnormal HR recovery had lower exercise capacity, and those with both had the lowest exercise capacity (P < .0001 compared with normal responses). Indices of abnormal diastolic function were correlated with abnormal HR recovery. In multivariable analysis, after age diastolic dysfunction (referent: normal diastolic function) was the strongest predictor of abnormal HR recovery (adjusted odds ratio [OR] 1.47, 95% confidence interval [CI] 1.20–1.80) and incrementally predictive of chronotropic incompetence (adjusted OR 1.42, 95% CI 1.16–1.74).ConclusionsDiastolic dysfunction is independently associated with abnormal HR recovery after symptom-limited exercise. Further studies are needed to determine if diastolic function modifies the adverse outcomes observed in those with abnormal HR recovery.  相似文献   
99.
Flow-mediated dilation (FMD) is the standard tool used to assess endothelial function. The premise behind the standard FMD test is that it serves as an endothelial-dependant nitric oxide bioassay; however, the endothelium may release additional dilatory molecules which contribute to FMD, most notably prostacyclin and endothelial-derived hyperpolarizing factor. The relative importance of these molecules to the dilatory response may vary substantially among individuals, particularly in response to a number of diseased states. This review discusses how each of these molecules may contribute to vasodilation, and considers the circumstances in which they may vary.  相似文献   
100.
The Heart Failure Adherence and Retention Trial (HART) provided an opportunity to determine adherence to evidence-based guidelines (EBG) in patients with heart failure (HF). Ten hospitals were the source of 692 patients with HF (EF < 40%). Physicians of patients with HF were classified as adherent to EBG if the patient chart audit showed they were on a beta-blocker, ACE-inhibitor (ACE-I), or angiotensin receptor blocker (ARB). Patients were classified as adherent to EBG if MEMS pill caps were used appropriately more than 80% of the time. Sixty-three percent of physicians prescribed evidence-based medications that were adherent to clinical practice guidelines. New York Heart Association (NYHA) III patients were less likely to be adherent (P < 0.001), as were those with renal disease (P < 0.001) and asthmatics (P < 0.001). Nonadherent physicians were less likely to treat patients with beta-blockers (39% vs 98%, P < 0.001) and ACE-I or ARBs (71% vs 98% P < 0.001). Thirty-seven percent of patients prescribed evidence-based therapy failed to use the MEMS pill cap bottles appropriately and were more likely a minority or higher NYHA class. Adherence to evidence-based therapy is less than optimal in HF patients based on a combination of both physician and patient nonadherence.  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