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   2997篇
  免费   257篇
  国内免费   63篇
耳鼻咽喉   97篇
儿科学   249篇
妇产科学   39篇
基础医学   333篇
口腔科学   160篇
临床医学   274篇
内科学   690篇
皮肤病学   82篇
神经病学   182篇
特种医学   337篇
外科学   192篇
综合类   155篇
预防医学   238篇
眼科学   13篇
药学   220篇
肿瘤学   56篇
  2021年   40篇
  2020年   14篇
  2019年   29篇
  2018年   41篇
  2017年   28篇
  2016年   38篇
  2015年   36篇
  2014年   60篇
  2013年   84篇
  2012年   76篇
  2011年   103篇
  2010年   69篇
  2009年   90篇
  2008年   104篇
  2007年   133篇
  2006年   122篇
  2005年   132篇
  2004年   94篇
  2003年   91篇
  2002年   96篇
  2001年   110篇
  2000年   93篇
  1999年   91篇
  1998年   89篇
  1997年   97篇
  1996年   77篇
  1995年   81篇
  1994年   49篇
  1993年   67篇
  1992年   71篇
  1991年   89篇
  1990年   77篇
  1989年   119篇
  1988年   88篇
  1987年   95篇
  1986年   71篇
  1985年   73篇
  1984年   48篇
  1983年   28篇
  1982年   31篇
  1981年   39篇
  1980年   35篇
  1979年   39篇
  1978年   23篇
  1977年   32篇
  1976年   19篇
  1975年   15篇
  1974年   15篇
  1973年   12篇
  1971年   10篇
排序方式: 共有3317条查询结果,搜索用时 328 毫秒
1.
2.
3.
4.
The health care resource allocation debate. Defining our terms   总被引:1,自引:0,他引:1  
D C Hadorn  R H Brook 《JAMA》1991,266(23):3328-3331
The problem of health care distribution in the United States demands immediate action. Many different solutions have been proposed to slow rising health care costs and to improve access to care for the poor and uninsured. Debate among proponents of these various proposals might be advanced if a common language were adopted with regard to certain key terms instead of the various meanings currently assigned to these terms. For this reason, we propose and defend the following three definitions: (1) rationing is the societal toleration of inequitable access to health services acknowledged to be necessary by reference to necessary-care guidelines; (2) health care needs are desires for services that have been reasonably well demonstrated to provide significant net benefit for patients with specified clinical conditions; and (3) basic benefit plans are insurance packages that provide for all and only acknowledged health care needs, again by reference to appropriate clinical guidelines.  相似文献   
5.
6.
7.
Homozygous familial hypercholesterolemia (HFH) is a very rare autosomal dominant disease characterized by accelerated severe atherosclerosis. We examined 18 patients from 9 families with HFH. The age range was 6-30 years (mean = 16 years). Male to female ratio was equal. All patients had huge, multiple tuberous xanthomas on the skin and tendons. Mean +/- standard deviation of plasma cholesterol, triglycerides, low-density lipoproteins (LDL), and high-density lipoproteins (HDL) cholesterol levels were 608 +/- 89, 122 +/- 39, 550 +/- 88, and 26 +/- 8 mg/dl, respectively. Five patients (28%) had angina pectoris, two sustained a myocardial infarction, and one died at the age of 15 years. Two-dimensional echocardiography demonstrated supravalvular aortic stenosis in 3 of the 13 patients (23%). Coronary arteriography performed in 11 patients demonstrated significant obstruction in 6 patients, 2 each with single-, double-, and triple-vessel disease. Left main stenosis was present in 3 patients (27%). Supravalvular aortic narrowing was demonstrated in 6 patients (54%) and was associated with a gradient in 2 (25 and 35 mmHg, respectively). Segmental contraction abnormalities were detected in 2 of the 11 patients (18%). It is concluded that coronary artery disease is prevalent in patients with HFH and, based on the data presented, we recommend the performance of noninvasive technique, coronary arteriography and supravalvular aortography at an early age to detect and to follow the progression of the disease.  相似文献   
8.
In 1984, 154 physicians who had completed residencies in internal medicine at 15 major teaching hospitals in 1982 evaluated their residency training in ambulatory care. A majority of the physicians would have liked more experience in practical areas related to career planning and office management, more input from subspecialties such as orthopedics and dermatology, greater knowledge about the management of psychosocial problems, and more information about exercise and nutrition. Although many physicians also wanted more time devoted to several other topics, less than 20 percent recommended spending less time on 26 of the 27 topics being evaluated. Since these recommendations are similar to those reported in evaluation studies published over the past 25 years, it appears that training programs in internal medicine have not been successful in restructuring their curricula to meet many of the needs of practicing physicians.  相似文献   
9.
10.
OBJECTIVE: To assess the utility and reliability of echocardiographic assessment of hemidiaphragm motion abnormalities in pediatric cardiothoracic patients. DESIGN: Retrospective observational study, with post hoc blinded assessment of echocardiographic and fluoroscopic results. SETTING: Tertiary care center. PATIENTS: Thirty-six consecutive pediatric cardiothoracic patients with suspected hemidiaphragm paralysis were identified and included in the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The results of both echocardiographic and fluoroscopic studies on all patients were included. In addition, blinded review of study results were performed. The sensitivity and specificity of fluoroscopy in identifying hemidiaphragms that needed plication were 100% and 74%, respectively. The positive predictive value was 55%; negative predictive value was 100%. Comparing reported diagnoses with blinded review of the studies showed poor agreement; reviewers agreed with 89% diagnosed as normal, 44% of paralyzed, and 76% of paradoxical hemidiaphragms. The sensitivity and specificity of echo in identifying hemidiaphragms that needed plication were 100% and 81%, respectively. The positive predictive value and negative predictive value were 66% and 100%. Comparing reported diagnoses with blinded review, reviewers agreed with 97% diagnosed as normal, 81% of paralyzed, and 100% of paradoxical hemidiaphragms. Echocardiography was less accurate in discriminating between paralyzed and paradoxical diaphragm motion. Echocardiography was specific for paradoxical motion, since both patients identified by echocardiography were confirmed by fluoroscopy, but it was not sensitive. In nine patients, echo showed paralyzed motion that was identified by fluoroscopy as paradoxical. CONCLUSIONS: This study supports the use of echocardiography in the assessment of diaphragm function. When the diaphragms are clearly visualized by echo, as they are in the majority of cases, the addition of an additional fluoroscopic study adds no clinical value. The differentiation between paralyzed and paradoxical motion is unreliable by both imaging modalities.  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