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   860篇
  免费   50篇
  国内免费   9篇
耳鼻咽喉   5篇
儿科学   39篇
妇产科学   9篇
基础医学   107篇
口腔科学   44篇
临床医学   75篇
内科学   175篇
皮肤病学   40篇
神经病学   28篇
特种医学   150篇
外国民族医学   1篇
外科学   71篇
综合类   39篇
预防医学   55篇
眼科学   5篇
药学   46篇
中国医学   1篇
肿瘤学   29篇
  2021年   3篇
  2020年   4篇
  2019年   7篇
  2018年   9篇
  2017年   13篇
  2016年   13篇
  2015年   25篇
  2014年   14篇
  2013年   28篇
  2012年   20篇
  2011年   23篇
  2010年   30篇
  2009年   45篇
  2008年   25篇
  2007年   17篇
  2006年   18篇
  2005年   13篇
  2004年   31篇
  2003年   18篇
  2002年   8篇
  2001年   6篇
  2000年   9篇
  1999年   21篇
  1998年   56篇
  1997年   63篇
  1996年   56篇
  1995年   43篇
  1994年   40篇
  1993年   37篇
  1992年   10篇
  1991年   12篇
  1990年   18篇
  1989年   16篇
  1988年   23篇
  1987年   24篇
  1986年   23篇
  1985年   12篇
  1984年   4篇
  1983年   8篇
  1982年   18篇
  1981年   3篇
  1980年   9篇
  1979年   4篇
  1978年   4篇
  1977年   5篇
  1976年   6篇
  1968年   3篇
  1966年   2篇
  1965年   2篇
  1959年   2篇
排序方式: 共有919条查询结果,搜索用时 188 毫秒
51.
Cyclophosphamide in a daily dose of 10 mg/kg was injected intraperitoneally in male Wistar rats for 15 days. Two rats each time were killed for testis examination at regular intervals within 100 days following treatment (over 2 spermatogenetic cycles). One hundred days after the end of the treatment, the other rats, whose spermatogenesis had recovered in the meantime, were mated with 3-month-old females. Offspring were evaluated in regard to the mean number per litter, sex ratio, frequency of gross external malformations, growth pattern, mortality in the first 4 months of life and reproductive ability at 6 months of age. Offspring behavior was also examined between 10 and 14 weeks of age. They were evaluated for spontaneous activity and emotionality with an open field test and for learning ability with an avoidance conditioning test. Cyclophosphamide induced a significant decrease in the number of primary spermatocytes and spermatozoa. Only learning ability was altered in the offspring from the treated males, for the animals which succeeded in the avoidance conditioning test did not learn as rapidly as the controls. However, the difference was significant only in the males. Behavioral abnormalities and the possible genetic factors involved are related to the particular concept of 'physioteratogenesis'.  相似文献   
52.
The effect of barium on blood in the gastrointestinal tract   总被引:2,自引:0,他引:2  
  相似文献   
53.
54.
Checketts  MR; Wildsmith  JAW 《CEACCP》2004,4(2):48-51
The last few years have seen increasing concerns among anaesthetistsabout the risks of pharmacological prophylaxis for thromboembolicdisease. Increased bleeding during or after surgery is one concern,but of greater significance is the possibility of an increasedpredisposition to haematoma formation when regional block isused. Most of the recent consideration of this problem has beenin relation to vertebral canal haematoma formation after centralnerve block. Some thought must be given also to the possibilityof haematoma formation after peripheral techniques when thetarget nerve is deeply placed so that pressure cannot be usedto control bleeding after needle insertion. However, this reviewwill be focused on vertebral canal haematoma.  相似文献   
55.
56.
BACKGROUND: By 2016, the proportion of Canadians older than 65 years of age will increase to 16%, and there will be an increase in the absolute number of cases of cardiovascular disease in older Canadians. The Canadian Heart Health Surveys database provides information about this population upon which health policy related to cardiovascular disease can be based. This paper presents for the first time population-based data on the risk factors for cardiovascular disease in older Canadians. METHODS: Canadians from all 10 provinces participated in surveys of cardiovascular risk factors; health insurance registries were used as sampling frames. In each province, probability samples of 2200 adults 18 to 74 years old not living in institutions, on reserves or in military camps were asked to participate in interviews and to undergo testing at clinics for major risk factors for cardiovascular disease. RESULTS: A total of 2739 men (response rate 70%) and 2617 women (response rate 66%) aged 55 to 74 years participated in the survey and also provided follow-up clinical measurements at the clinic. Overall, 52% of participants were hypertensive, 26% had isolated systolic hypertension, and 30% had a total blood cholesterol level of 6.2 mmol/L or greater. Rates of current smoking were lower in women than men (17% v. 22%). Overall, 87% of men and 78% of women who were current smokers smoked at least 10 cigarettes per day. Only slightly more than half of participants exercised at least once a week for at least 15 minutes, and almost half had a body mass index of 27 or greater. In only 4% was no major risk factor for cardiovascular disease detected. INTERPRETATION: Significant numbers of older Canadians have one or more major risk factors for cardiovascular disease. Many of these risk factors are amenable to modification.  相似文献   
57.
口服Carvedilol治疗心力衰竭多中心研究(MOCHA)   总被引:1,自引:0,他引:1  
标题 Carvedilol对慢性心力衰竭患者左心室功能的改善和存活的提高呈剂量相关性作者 BristowMR,GilbertEM,AbrahamWT,等  Circulation1996,94:2807~2816  研究疾病:充血性心力衰竭。目的:对Carvedilol治疗慢性心力衰竭患者剂量-疗效特征进行评价。  设计:随机、双盲、安慰剂对照的多中心研究,剂量效应关系研究。病人资料:共345名心力衰竭患者,年龄18~85岁,左室射血分数≤0-35,心力衰竭症状时间≥3月,研究前所有患者必须用利…  相似文献   
58.
Volumetric rendering of MR images   总被引:1,自引:0,他引:1  
The authors developed new techniques for three-dimensional display of magnetic resonance (MR) images that preserve soft-tissue definition, are fully automatic, and work with routinely used section thicknesses. MR images are segmented, selectively enhanced, and displayed by means of a volumetric rendering algorithm. These techniques were used to illustrate normal anatomy of the brain, knee, and liver. Three-dimensional rendering of balanced spin-echo images shows the ventricles and extracerebral veins and of T1-weighted images, the sulci and gyri. The large hepatic and portal vessels can be seen with these enhancement techniques. Three-dimensional views of the knee reveal articular surfaces of the tibia and clearly depict menisci and posterior and anterior cruciate ligaments. These techniques make it possible to image multiple soft tissues simultaneously while preserving the detail contained in the original images. Three-dimensional presentation of complex, overlapping anatomic regions is helpful in surgical planning and should lead to improved diagnosis.  相似文献   
59.
60.
Pulmonary manifestations of AIDS: review of 106 episodes   总被引:9,自引:0,他引:9  
Suster  B; Akerman  M; Orenstein  M; Wax  MR 《Radiology》1986,161(1):87-93
We reviewed the clinical records and chest radiographs of all patients admitted to our institution between 1982 and 1984 who had pulmonary disease and who were later proved to have acquired immunodeficiency syndrome (AIDS) (95 patients). Diffuse parenchymal lung disease was the most common finding. These infiltrates were usually interstitial and caused by Pneumocystis carinii pneumonia or P. carinii combined with cytomegalovirus infection. Focal, multilobar, interstitial infiltrates were also often seen and usually caused by P. carinii or P. carinii and cytomegalovirus infections. Rarely, well-defined, multiple, interstitial nodules less than 10 mm in diameter were the only or predominant characteristic and were seen only in association with Mycobacterium tuberculosis or Cryptococcus neoformans infections or Kaposi sarcoma. Hilar or mediastinal adenopathy occurred in 17 of the 21 patients with M. tuberculosis or C. neoformans infections. In contrast, only 4% of patients with P. carinii infections presented with these findings. We also found that hilar or mediastinal adenopathy was not significantly associated with peripheral adenopathy. Lung cavitation, pleural effusion, or a normal chest radiograph was uncommon.  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