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   3999篇
  免费   383篇
  国内免费   4篇
耳鼻咽喉   62篇
儿科学   252篇
妇产科学   60篇
基础医学   530篇
口腔科学   49篇
临床医学   346篇
内科学   857篇
皮肤病学   69篇
神经病学   262篇
特种医学   329篇
外科学   376篇
综合类   108篇
一般理论   7篇
预防医学   379篇
眼科学   122篇
药学   243篇
中国医学   2篇
肿瘤学   333篇
  2021年   50篇
  2020年   36篇
  2019年   33篇
  2018年   60篇
  2017年   44篇
  2016年   34篇
  2015年   65篇
  2014年   78篇
  2013年   112篇
  2012年   154篇
  2011年   163篇
  2010年   104篇
  2009年   88篇
  2008年   149篇
  2007年   167篇
  2006年   134篇
  2005年   129篇
  2004年   145篇
  2003年   137篇
  2002年   131篇
  2001年   130篇
  2000年   127篇
  1999年   114篇
  1998年   69篇
  1997年   90篇
  1996年   81篇
  1995年   71篇
  1994年   67篇
  1993年   77篇
  1992年   95篇
  1991年   105篇
  1990年   106篇
  1989年   131篇
  1988年   114篇
  1987年   105篇
  1986年   103篇
  1985年   92篇
  1984年   62篇
  1983年   67篇
  1982年   49篇
  1981年   45篇
  1980年   42篇
  1979年   40篇
  1978年   33篇
  1976年   35篇
  1975年   39篇
  1974年   28篇
  1973年   28篇
  1972年   27篇
  1971年   29篇
排序方式: 共有4386条查询结果,搜索用时 15 毫秒
11.
12.
This study describes the manipulation of secondary products arising from the synthesis of the prototypical molecular combination of 5-fluorouracil (5-FU) and chloroethylnitrosourea (CNU), B.3839, in order to investigate the effects produced by connecting the C-S-C-C-CNU chain to the 5-FU ring in different ways. The isolation of phthalimide precursors of these compounds and the transformation into CNUs is described. Anti-tumour activity of these molecular combinations against a series of experimental murine colon, lung and mammary tumours is presented. The spectrum of anti-tumour activity displayed is interesting but defies simple explanation without further detailed in vivo pharmacokinetic and metabolism studies in order to define optimal profiles for activity.  相似文献   
13.
14.
15.
The liver, skeletal muscle, and adrenal gland obtained from two nine-banded armadillos infected with Mycobacterium leprae were studied using an electron microscope. M. leprae were found in varying numbers inside hepatocytes, Kupffer's cells, striated muscle cells, adrenal cortical and adrenal medullary cells, endothelial cells, and macrophages. There was evidence to suggest that M. leprae were actively phagocytosed by the liver and skeletal muscle cells. The inert nature of M. leprae and its behavior as an almost ideal parasite of parenchymal cells are emphasized. The question of whether this unique parasitism of parenchymal cells and the possible processing and presentation of M. leprae antigens by these cells could be responsible for aberrant immune responses is raised.  相似文献   
16.
17.
Cerebral arterial aneurysm associated with arteriovenous malformation (AVM) has been described with a variable incidence, averaging 10% of AVM cases. The present series includes 39 patients with this association, derived from a total of 400 patients with AVM's evaluated and treated since 1970. The aneurysms are classified into four major groups, each carrying particular therapeutic implications. Optimum treatment of these lesions is based in part on a knowledge of the hemodynamic alterations associated with the AVM's. In most of these cases, the symptomatic lesion was treated first; occasionally, when feasible, both lesions were treated during the same operation. All patients had some form of treatment, either surgical or endovascular, directed to at least one of the two types of lesions. All symptomatic lesions were treated and all ruptured aneurysms were obliterated. There were no deaths in this series.  相似文献   
18.
Radiation therapy in breast conservation patients and postmastectomy.   总被引:1,自引:0,他引:1  
Radiation has played a continuous but changing role in the management of breast cancer. At Memorial Hospital, the past 10 years have seen a marked increase in breast conserving therapy, and changing indications for postmastectomy adjuvant radiation.  相似文献   
19.
Pregnant women with epilepsy have a greater risk for complications of pregnancy and adverse pregnancy outcomes. Problems that may arise during the course of pregnancy include an increase in seizure frequency, reduction of serum antiepileptic drug levels, and an increase in bleeding during pregnancy and after delivery. The infant of an epileptic mother is at twice the risk of infants in the general population to have a major malformation, and the risk for perinatal death is 1.2 to 3 times greater. Despite these facts, at least 90% of women with epilepsy have a normal pregnancy and deliver a normal infant. The pregnant woman with epilepsy may minimize the risk of adverse outcome by taking measures to ensure an optimal prenatal course. The neuroscience nurse can provide these clients with accurate information regarding pregnancy and epilepsy and can review measures that may be taken to reduce chances of an unfavorable outcome.  相似文献   
20.
Hodgkin disease: CT of the thymus   总被引:2,自引:0,他引:2  
Heron  CW; Husband  JE; Williams  MP 《Radiology》1988,167(3):647-651
The computed tomography (CT) scans in two groups of patients with Hodgkin disease were reviewed to determine the frequency of thymic enlargement. In 50 CT scans from 50 patients with evidence of thoracic disease on CT scans who were examined for primary staging, the thymus was enlarged in 15 of 50 (30%). Fifty CT scans were obtained from 44 patients at the time of 50 separate episodes of known or suspected relapse. Relapse occurred in the mediastinum in 12 episodes, lung parenchyma in five, and both sites in one. Thymic enlargement thought to be due to involvement by disease was present in seven of 18 (38%). Mediastinal disease was associated with thymic enlargement in all but one patient in whom a thymic cyst developed after radiation therapy. Differentiation of thymic enlargement from enlarged superior mediastinal lymph nodes was easily made in all but two patients. Thymic enlargement in the absence of lymph node enlargement may indicate a different disease, since isolated Hodgkin disease of the thymus is uncommon. Primary thymic tumor should be considered initially, whereas after treatment, rebound hyperplasia of the thymus may be the cause of enlargement.  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