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   1031篇
  免费   50篇
  国内免费   4篇
耳鼻咽喉   1篇
儿科学   73篇
妇产科学   11篇
基础医学   103篇
口腔科学   27篇
临床医学   95篇
内科学   232篇
皮肤病学   21篇
神经病学   32篇
特种医学   254篇
外科学   102篇
综合类   12篇
预防医学   38篇
眼科学   4篇
药学   36篇
中国医学   1篇
肿瘤学   43篇
  2023年   3篇
  2022年   2篇
  2021年   3篇
  2020年   4篇
  2019年   5篇
  2018年   16篇
  2017年   13篇
  2016年   7篇
  2015年   11篇
  2014年   24篇
  2013年   23篇
  2012年   25篇
  2011年   19篇
  2010年   40篇
  2009年   43篇
  2008年   32篇
  2007年   25篇
  2006年   29篇
  2005年   25篇
  2004年   15篇
  2003年   16篇
  2002年   10篇
  2001年   15篇
  2000年   8篇
  1999年   14篇
  1998年   51篇
  1997年   66篇
  1996年   49篇
  1995年   41篇
  1994年   52篇
  1993年   52篇
  1992年   12篇
  1991年   16篇
  1990年   13篇
  1989年   38篇
  1988年   40篇
  1987年   28篇
  1986年   28篇
  1985年   27篇
  1984年   11篇
  1983年   21篇
  1982年   18篇
  1981年   18篇
  1980年   22篇
  1979年   4篇
  1978年   8篇
  1977年   12篇
  1976年   9篇
  1975年   17篇
  1948年   1篇
排序方式: 共有1085条查询结果,搜索用时 15 毫秒
991.
Whole-breast US imaging: four-year follow-up   总被引:3,自引:1,他引:2  
Kopans  DB; Meyer  JE; Lindfors  KK 《Radiology》1985,157(2):505-507
Between March 1980 and April 1981, 1,140 women underwent physical examination, xeromammography, and whole-breast ultrasound (US) using a whole-breast water path system. Results of each study were interpreted independently by separate observers in a blind fashion. Biopsy revealed 125 cancers in 127 breasts. Findings were considered to be suspicious for carcinoma in 199 women based on physical examination, in 201 based on mammograms, and in 255 based on US scans. Physical examinations were able to reveal 91% (115/127) of the cancers, reflecting the referral nature of the population, and failed to detect 12 lesions. Mammograms disclosed 94% (119/127) of the cancers, including 12 clinically occult lesions, but did not show eight palpable cancers. US scans disclosed only 64% (81/127) of the cancers, all of which were palpable. In a 4-year follow-up, no cancers have appeared in the group that had suspicious findings by US only. We conclude that US should not be used routinely to screen women for breast cancer.  相似文献   
992.
993.
Goodman  LR; Troup  PJ; Thorsen  MK; Youker  JE 《Radiology》1985,155(3):571-573
The automatic implantable cardioverter-defibrillator is used in patients with ventricular tachyarrhythmias resistant to medical or surgical therapy. The device, which has a unique radiographic appearance, senses ventricular tachycardia or fibrillation and automatically delivers a cardioverting or/defibrillating electric shock.  相似文献   
994.
995.
Laposata  M; Krueger  CM; Saffitz  JE 《Blood》1987,70(3):832-837
We have used quantitative electron microscopic autoradiography to characterize the subcellular distribution of arachidonoyl phospholipids following brief (5 minutes) exposure of unstimulated human platelets to [3H]arachidonic acid. Labeled arachidonate was taken up rapidly and incorporated into phospholipids. Phospholipid radioactivity was preserved and spatially fixed during tissue processing for electron microscopy. Analysis of autoradiographs showed that following a brief exposure to 750 nmol/L [3H]arachidonate, there is selective labeling of an internal membrane compartment composed of the dense tubular system and the open canalicular system. The plasma membrane, platelet granules, and nonmembranous cytoplasm were not labeled. Since the open canalicular system is continuous with the plasma membrane and since phospholipids in continuous membranes are freely diffusible, our observations indicate that [3H]arachidonate was incorporated into phospholipids within the dense tubular system and not the open canalicular system. Thus, the dense tubular system, known to contain cyclooxygenase activity, incorporates arachidonate selectively following brief exposure to this fatty acid, presumably to concentrate it in proximity to enzymes for icosanoid synthesis.  相似文献   
996.
997.
Mandatory preparticipation examinations (PPE) are labor intensive, offer little routine health maintenance and are poor predictors of future injury or illness. Our objective was to develop a new PPE for the Stanford University varsity athletes that improved both quality of primary and preventive care and physician time efficiency. This PPE is based on the annual submission, by each athlete, of a comprehensive medical history questionnaire that is then summarized in a two-page report for the examining physician. The questionnaire was developed through a search of MEDLINE from 1966 to 1997, review of PPE from 11 other institutions, and discussion with two experts from each of seven main content areas: medical and musculoskeletal history, eating, menstrual and sleep disorders, stress and health risk behaviors. Content validity was assessed by 10 sports medicine physicians and four epidemiologists. It was then programmed for the World Wide Web (http:// www.stanford.edu/dept/sportsmed/). The questionnaire demonstrated a 97 +/- 2% sensitivity in detecting positive responses requiring physician attention. Sixteen physicians administered the 1997/98 PPE; using the summary reports, 15 found improvement in their ability to provide overall medical care including health issues beyond clearance; 13 noted a decrease in time needed for each athlete exam. Over 90% of athletes who used the web site found it "easy" or "moderately easy" to access and complete. Initial assessment of this new PPE format shows good athlete compliance, improved exam efficiency and a strong increase in subjective physician satisfaction with the quality of screening and medical care provided. The data indicate a need for improvement of routine health maintenance in this population. The database offers opportunities to study trends, risk factors, and results of interventions.  相似文献   
998.
The authors examined 19 patients with diffuse histiocytic lymphoma of the brain, including 8 with primary disease and 11 with secondary disease. Both primary disease and secondary disease involving the brainstem and deep nuclei exhibited the characteristic CT appearance, consisting of a large, solid, homogeneously enhanced mass with varying amounts of edema. However, most secondary lymphomas outside the brainstem and basal ganglia contained large areas of low attenuation consistent with necrosis. Multifocal lesions were seen only in patients with secondary lymphoma. Systemic chemotherapy for extracranial lymphoma had no effect on the CT appearance of intracranial lesions. The authors suggest that these "unusual" CT patterns are actually typical of a distinct subset of histiocytic lymphomas.  相似文献   
999.
1000.
Quality of life in children with congenital heart defects   总被引:1,自引:0,他引:1  
Quality of life was measured in children with congenital heart defects (CHDs) registered in a total population of infants born live in the period 1982–91 ( n = 22 810), using essential life spheres: external living conditions, interpersonal and personal conditions. In 200 children with CHD alive at the time the investigation was performed, 164 (82%) of the families answered a questionnaire addressing different dimensions of these quality of life spheres. Three subgroups of CHDs were investigated: CHDs spontaneously cured ( n = 80), CHDs treated by surgery ( n = 56), and CHDs with associated syndromes/ malformations ( n = 29). 301 (75%) out of 400 controls, matched for age and habitat (county), answered the same questionnaire. The children's ages at investigation were 2y 2 months-12y 2 months (median 6y 1 month). There were no statistically significant differences between the CHD groups and the controls for overall quality of life for any of the three life spheres ( p > 0. 05). In children with operated CHDs and CHDs associated with syndromes/malformations, quality of life was influenced at some aspects of the external as well as at the interpersonal and personal levels. A trend existed for a higher subjective experience of quality of life in the total CHD group as well as in all the subgroups. It is speculated that this may represent development of coping mechanisms and recalibration of values of life.  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