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   653篇
  免费   18篇
耳鼻咽喉   4篇
儿科学   23篇
妇产科学   24篇
基础医学   79篇
口腔科学   8篇
临床医学   149篇
内科学   152篇
皮肤病学   10篇
神经病学   46篇
特种医学   8篇
外科学   55篇
综合类   17篇
预防医学   39篇
眼科学   13篇
药学   23篇
肿瘤学   21篇
  2017年   3篇
  2016年   5篇
  2015年   5篇
  2014年   3篇
  2013年   10篇
  2012年   3篇
  2011年   3篇
  2010年   13篇
  2009年   10篇
  2008年   3篇
  2007年   4篇
  2005年   3篇
  2004年   3篇
  2003年   4篇
  2001年   4篇
  2000年   3篇
  1999年   8篇
  1998年   14篇
  1997年   23篇
  1996年   14篇
  1995年   14篇
  1994年   17篇
  1993年   16篇
  1992年   13篇
  1991年   7篇
  1990年   13篇
  1989年   10篇
  1988年   12篇
  1987年   6篇
  1986年   5篇
  1985年   8篇
  1984年   10篇
  1983年   12篇
  1981年   10篇
  1980年   5篇
  1979年   4篇
  1978年   5篇
  1976年   3篇
  1975年   4篇
  1973年   4篇
  1970年   3篇
  1969年   2篇
  1959年   37篇
  1958年   54篇
  1957年   56篇
  1956年   56篇
  1955年   39篇
  1954年   45篇
  1949年   21篇
  1948年   21篇
排序方式: 共有671条查询结果,搜索用时 31 毫秒
1.
2.
3.
Health care services and resources for older persons living in rural areas may be highly variable, and integrated service-delivery models are often lacking. This article presents a managed-care model of nutrition risk screening and intervention for older persons in rural areas. Nutrition risk screening was implemented by the Geisinger Health Care System, Danville, Pa, to target all eligible enrollees in a regional Medicare risk program. A single remote clinic site participating in the managed health care system was chosen for further study of a linked screening and case-management effort for undernourished persons. Screening and intervention at the clinic site selected for this study were guided by centralized expertise and resources. Individualized evaluation and intervention plans were developed with the aid of a dietitian and implemented by the clinic case manager. Of the 417 subjects who completed screening at the remote site, 68 met the risk criteria for undernutrition and were selected for case management. Many of the targeted persons received interventions that included evaluations by a physician or physician extender (eg, physician assistant, nurse practitioner) at the clinic and consultations with nutrition, mental health, or social services professionals. Twenty-six of the subjects who took part in the intervention completed a follow-up screening 6 months later. Ten of those persons no longer exhibited risk criteria. This demonstrates the feasibility of a linked screening and case management program for nutrition risk in the managed-care setting. J Am Diet Assoc. 1997; 97: 885-888.  相似文献   
4.
Abstract: To perform the first experimental tests for validation of a new gear unit concept, the pump chamber, diaphragm, and pusher plate design of an orthotopic electromechanical total artificial heart (TAH) (Helmholtz Labtype) was manufactured. In its early stage of development, it provides some of the most important features of the conceptual final artificial heart. The new gear unit transforms a uniform unidirectional rotational motor movement into translatory pusher plate movements, with resting phase in the end–diastolic position, and the angled pump chamber orientation determines the available space for the motor and gear unit. Furthermore, this labtype provides flexibility with regard to use of different types of structural parts for experimental investigations. The first in vitro test results, obtained with specially designed circulatory mockloops that simulate physiological preload and afterload conditions, are presented. They comprise pressure and flow generation, motor performance, efficiency, and energy consumption. The results prove the feasability of the new gear unit concept for an electromechanical artificial heart and allow a reliable determination of the necessary performance of the future brushless DC motor for the first in vivo TAH model.  相似文献   
5.
6.
BACKGROUND: Gastrointestinal spasms and cramps are common in children as well as in adults. Alternative medical practices such as chiropractice and homeopathy are becoming increasingly popular in Europe and the USA. The effectiveness and tolerability of the homeopathic preparation Spascupreel was compared with that of hyoscine butylbromide treatment in children <12 years of age. METHODS: An observational cohort study in 204 children <12 years was conducted over a 1 week treatment period. The efficacy of the respective therapies were evaluated on the effect on severity of spasms and clinical symptoms (pain/cramps, sleep disturbances, distress, eating or drinking difficulties and frequent crying). Compliance was evaluated on a four-point scale from 'very good' to 'low'. Evaluation was done by the practitioner based on information given by the patient or minder. RESULTS: The analysis showed comparative improvements with the homeopathic preparation and hyoscine butylbromide therapy on severity of spasms, pain/cramps, sleep disturbances, eating or drinking difficulties, and frequent crying, all as evaluated by the practitioner. Both treatments were very well tolerated. CONCLUSIONS: For patients opting for a homeopathic therapy, Spascupreel seems to be an effective and well tolerated alternative to conventional therapies in children suffering from gastrointestinal spasms.  相似文献   
7.
8.
9.
Syncope is a complex symptom with multiple potential etiologies that can be difficult to establish. The major obstacles to diagnosis are the periodic and unpredictable nature of events and the high spontaneous remission rate. Short-term ECG monitoring often is unproductive when initial noninvasive testing is negative due to the low probability of recurrence during the brief monitoring period. Implantable loop recorders extend the ability to monitor cardiac patients, enhancing the diagnostic yield to as high as 85% in difficult to diagnose syncope. Several recent studies suggest that prolonged monitoring with an implantable loop recorder has a role in patients with syncope and conduction disturbances, negative tilt testing, and unexplained seizures, and may be superior to conventional testing with tilt and electrophysiologic studies. (J Cardiovasc Electrophysiol, Vol. 14, pp. S70-S73, September 2003, Suppl.)  相似文献   
10.
Dopexamine hydrochloride (Dopacard®) is a new syntheticcatecholamine compound, which possesses potent ß2-adrenergicand D A 1-dopaminergic agonistic properties. It is free of a-adrenergicactivity, has no ß1-adrenergic activity and is lesspotent at D A2-dopaminergic receptors than dopamine. In thepresent study the acute haemodynamic effects of dopexamine hydrochloridewere compared to those of dobutamine and nitroprusside in 12patients with idiopathic congestive cardiomyopathy in an opencrossover study. With dopexamine hydrochloride, there were dose-dependentincreases from control in cardiac output and stroke volume,decreases in blood pressure, right and left atrial pressure,systemic vascular resistance and pulmonary vascular resistanceand little change in heart rate. Similar effects were seen withnitroprusside, apart from a marked increase in heart rate, andwith dobutamine, except that systolic aortic blood pressureincreased and there was no change in diastolic or mean pressureor pulmonary artery systolic pressure. In general, dopexamine hydrochloride produced effects betweenthose produced by the other two treatments. This suggests thatdopexamine with its combined vasodilator and inotropic actionhas a desirable cardiovascular profile with advantages overthe ß1-receptor aganist dobutamine and the pure vasodilatorsodium nitroprusside.  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