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   11740篇
  免费   1076篇
  国内免费   14篇
耳鼻咽喉   215篇
儿科学   328篇
妇产科学   550篇
基础医学   1605篇
口腔科学   377篇
临床医学   1193篇
内科学   2609篇
皮肤病学   113篇
神经病学   1485篇
特种医学   467篇
外国民族医学   1篇
外科学   1533篇
综合类   196篇
一般理论   2篇
预防医学   675篇
眼科学   235篇
药学   644篇
中国医学   2篇
肿瘤学   600篇
  2021年   121篇
  2019年   130篇
  2018年   152篇
  2017年   132篇
  2016年   117篇
  2015年   151篇
  2014年   208篇
  2013年   330篇
  2012年   414篇
  2011年   449篇
  2010年   288篇
  2009年   306篇
  2008年   411篇
  2007年   440篇
  2006年   453篇
  2005年   443篇
  2004年   410篇
  2003年   382篇
  2002年   403篇
  2001年   369篇
  2000年   377篇
  1999年   295篇
  1998年   131篇
  1997年   149篇
  1996年   149篇
  1995年   117篇
  1994年   114篇
  1993年   123篇
  1992年   252篇
  1991年   256篇
  1990年   291篇
  1989年   289篇
  1988年   285篇
  1987年   287篇
  1986年   260篇
  1985年   283篇
  1984年   220篇
  1983年   168篇
  1982年   145篇
  1981年   138篇
  1979年   200篇
  1978年   157篇
  1977年   142篇
  1976年   115篇
  1975年   103篇
  1974年   159篇
  1973年   146篇
  1972年   117篇
  1971年   106篇
  1970年   108篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Estimating the economic costs of a disease is an important prerequisite to determining the costs and benefits of various preventive programs. For preventive programs, incidence-based costing is a more appropriate means of estimation than is prevalence-based costing. In this study the cost of acute myocardial infarction (AMI) in New South Wales has been estimated using an incidence-based approach. The calculated cost of AMI in 1979 was $301.0 million, made up of $32.3 million as direct costs and $268.7 million as indirect costs. In a sensitivity analysis, the cost was shown to be most sensitive to the incidence of AMI, the discount rate, and the assumption of a wage for housework. Both the direct costs and indirect costs per case are substantially higher in the United States than in Australia, and this reflects higher physician charges, higher hospital costs, and in the case of indirect costs, higher average weekly earnings.  相似文献   
12.
13.
This paper outlines the programming model employed by the Soul City Institute for Health and Development Communication, a South African NGO, in using ‘edutainment’ to facilitate social change. The paper refers to the intersection of this model and current thought on health promotion and various social change theories. It also discusses key challenges and factors contributing to sustainability over 12 years.  相似文献   
14.
We have used tissue expanders to treat 10 patients with breast deformities, 2 the result of burns and 8 congenital in origin. The expanders are placed in the subglandular plane and expanded incrementally until the desired amount of growth is obtained. In patients with congenital deformities, the desired size of the reconstructed breast (implant size) is determined during the expansion phase. Reconstructions of the nipple-areola complex are done either at the time of the exchange or as separate procedures. Patients with burn deformities present a variety of problems not seen with the congenital deformities. The expander is placed in the subglandular plane and filled to the desired volume. We have noted a marked permanent softening of the scar and grafts encasing the breast, which persists after the expander is removed and the breast reconstructed. The interval between expansion and definitive reconstruction is delayed for several months to allow scar softening to take place. If the parenchyma is not burned and pedicle tissue is not required, the expander can be deflated and the skin coverage observed to determine if it will remain soft. If it does, the expander can be removed and the breast reconstructed. In patients who require pedicle coverage in the reconstruction and who have unburned scar surrounding the breast, massive overexpansion is carried out. The pedicle skin is used to resurface the breast after removal of the appropriate areas of scar and skin grafts. In all burned patients, the inframammary fold must be reconstructed if the breast is to be protuberant. The nipple-areola complex also requires reconstruction. To date there has been great acceptance by patients with both congenital and burn deformities; however, we believe that tissue expansion techniques offer possibilities that have not as yet been fully explored.  相似文献   
15.
Cardiogenic shock complicating acute myocardial infarction (MI) carries a high mortality which in some series prior to 1980 exceeded 80%. Neither the use of inotropic and vasopressor agents nor intraaortic balloon counterpulsation was found to improve survival in this group of patients. Intravenous thrombolytic agents improve survival in patients with acute MI, but their role in cardiogenic shock is unknown. Reports of the use of surgical and mechanical interventions in patients with severe left ventricular dysfunction were examined to determine if there was any benefit to be derived from restoring blood flow to ischemic areas of the myocardium. It was found that urgent placement of intraaortic balloon counterpulsation followed by coronary bypass surgery may improve survival rates and successful coronary angioplasty also appeared to benefit patients with cardiogenic shock. Similar improvement in survival has been reported after successful coronary reperfusion. In surgical series with predominantly nonmechanical causes of shock, survival has varied from 40% to 88%. Data from our five-year experience in the management of MI patients with cardiogenic shock suggest that coronary revascularization with coronary angioplasty or bypass surgery improves survival in patients with cardiogenic shock especially when performed within 24 hours of the onset of shock.  相似文献   
16.
Diagnosis Related Group (DRG) hospital payment has begun to squeeze hospitals financially and is likely to do so in the future. This study analyzed the relationship between the volume of urologic procedures by an individual urologist, hospital costs per patient, and outcome. We used a three-year DRG database of urology patients (N = 2,980) at an academic medical center to analyze these. Low-volume urologists (arbitrarily defined by us) had higher hospital costs per patient, financial losses versus profits under DRGs, and a poorer outcome when compared with high-volume urologists. Pearson correlation showed a positive relationship between cost per patient and physician volume for nonemergency patients (-0.129, p less than 0.0001) and emergency patients (-0.368, p less than 0.0001). This may have been explained (in part) by a greater severity of illness for patients of low-volume urologists. These findings suggest, however, that the volume of urologic procedures per urologist may be related to hospital resource consumption. The health care financing environment of the future should provide substantial interest in this finding for those involved in the consumption of urologic services.  相似文献   
17.
Trazodone hydrochloride is an oral antidepressant agent which has been associated with the improvement of erections in impotent men and the development of prolonged erections or priapism in potent men. An in vivo study in animal and human subjects was performed to gain experience with the effect of intracavernosal trazodone. In the anesthetized New Zealand White rabbit, intracavernosal trazodone or its major metabolite m-chlorophenylpiperazine (m-CPP) produced full penile erection in 76% and 84% of animals studied respectively with doses ranging from one to 15 mg. On the other hand, intracavernosal administration of five mg. papaverine resulted in a prolonged erection in 90% of animals studied. In 13 selected volunteer patients, intracavernosal trazodone caused tumescence but not full penile erection with corporal body pressures of 28.2 +/- 5.8 mm. Hg. Intracavernosal papaverine or papaverine and phentolamine in these subjects resulted in significantly higher corporal body pressures of 58 +/- 18 mm. Hg (p less than .05). Intracavernosal administration of alpha adrenoceptor agonists but not normal saline resulted in complete detumescence of trazodone- or m-CPP-induced prolonged erection in the animal studies. Intracavernosal trazodone results in erectile activity that appears in part based on its local alpha blocking activity but like other intracavernosal alpha-blocking agents is not as effective in initiating penile erections as are intracavernosal agents that directly induce smooth muscle relaxation.  相似文献   
18.
Race/ethnicity and gender differences in the drugs-violence relationship   总被引:1,自引:0,他引:1  
This article examines the drug relatedness of violent events reported by White, Black, and Hispanic male and female street drug users from New York City. The primary purpose is to determine if the drugs-violence relationship varies for these different populations of drug abusers. Drug relatedness is assessed according to a tripartite conceptual model of the general relationship between drugs and violence. Significant race/ethnicity and gender differences were found in regard to the number of violent events manifesting specific drug-related dimensions of violence, the drugs associated with these violent events, and the primary reasons for the occurrence of these events. The implications of these findings are discussed.  相似文献   
19.
Although the influence of lung volume reduction surgery (LVRS) on incremental- and constant-power exercise is important in the evaluation of this procedure for patients with chronic obstructive pulmonary disease (COPD), it is rarely reported even in large randomised controlled trials. This report describes 39 patients with severe COPD ((mean +/- SE) forced expiratory volume in one second 32 +/- 2% pred, functional residual capacity 195 +/- 6% pred) who participated in a randomised controlled trial of LVRS and who completed incremental exercise tests at 6 months as well as endurance tests (constant power of 25 +/- 1 W) at 3, 9 and 12 months. Peak oxygen uptake (V'O2,pk) was similar between the treatment (n = 19) and control groups (n = 20) at baseline. After LVRS, the treatment group had a significantly greater V'O2,pk (mean difference (95% CI) 1.28 (0.07-2.50) mL x kg x min(-1)) and power (13 (6-20) W). The treatment group achieved a significantly greater minute ventilation (7.1 (2.9-11.3) L x min(-1)) with a greater tidal volume (0.16 (0.04-0.28) L). Baseline endurance was similar between groups. After surgery, there were significant between-group differences in endurance time, which were maintained at 12 months (7.3 (3.9-10.8) min). Lung volume reduction surgery is associated with an increase in exercise capacity and endurance, as compared with conventional medical treatment.  相似文献   
20.
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