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   899557篇
  免费   62429篇
  国内免费   2334篇
耳鼻咽喉   12474篇
儿科学   28676篇
妇产科学   26143篇
基础医学   126575篇
口腔科学   24686篇
临床医学   74750篇
内科学   183137篇
皮肤病学   18984篇
神经病学   71386篇
特种医学   36445篇
外国民族医学   336篇
外科学   142110篇
综合类   19030篇
一般理论   247篇
预防医学   64556篇
眼科学   20084篇
药学   63805篇
中国医学   1798篇
肿瘤学   49098篇
  2018年   9048篇
  2017年   7160篇
  2016年   7674篇
  2015年   8722篇
  2014年   12367篇
  2013年   19211篇
  2012年   25647篇
  2011年   27258篇
  2010年   16572篇
  2009年   15780篇
  2008年   26124篇
  2007年   27731篇
  2006年   27913篇
  2005年   27446篇
  2004年   26292篇
  2003年   25461篇
  2002年   25051篇
  2001年   41356篇
  2000年   42551篇
  1999年   36265篇
  1998年   9966篇
  1997年   9148篇
  1996年   9082篇
  1995年   8445篇
  1994年   8081篇
  1993年   7584篇
  1992年   28198篇
  1991年   26979篇
  1990年   26408篇
  1989年   25345篇
  1988年   23553篇
  1987年   23170篇
  1986年   22250篇
  1985年   21151篇
  1984年   15806篇
  1983年   13477篇
  1982年   8087篇
  1979年   14589篇
  1978年   10208篇
  1977年   8627篇
  1976年   8147篇
  1975年   8959篇
  1974年   10697篇
  1973年   10182篇
  1972年   9661篇
  1971年   8917篇
  1970年   8584篇
  1969年   8025篇
  1968年   7684篇
  1967年   7086篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
With the aim of defining a program of prevention for preneoplastic and neoplastic endometrial pathology which guarantees a valid, accurate and cost-contained diagnosis, 476 women considered at risk were examined. All the patients were first submitted to cytologic endocavitary withdrawal and subsequently to aspirated curettage. The cytologic and the histologic diagnoses proved concordant in 72.3% of cases of non-pathologic endometrium, in only 68.7% of preneoplastic pathology, and in 72.7% of neoplastic pathology. The non-interpretable pictures had a notable incidence (21.7%). The AA., while recognising the validity of cytology in cases of carcinoma, underline the difficulties in the diagnosis of preneoplastic lesions, and conclude that in doubtful or positive cases and subjects at risk a histologic enquiry is always necessary.  相似文献   
993.
The Istituto Rizzoli-Beretta experience with osteosarcoma of the jaw   总被引:2,自引:0,他引:2  
Twenty-eight osteosarcomas (OS) of the jaw were reported. There were 15 male and 13 female patients (age range, 9 to 68 years; mean, 36.9 years); 57.1% of the patients were older than 30 years of age. Swelling was the most frequent symptom; it was reported on an average of 6 months before diagnosis. Most of the tumors of the maxilla (eight patients) occurred in the alveolar ridge (six of eight). In the mandible (20 patients), the body was the preferred site (11 of 20). Radiographically most of the lesions were either lytic and sclerotic or only lytic. Histologically, 12 cases (42.9%) were osteoblastic osteosarcoma, ten (35.8%) were chondroblastic, four (14.3%) were fibroblastic, and two (7%) were round cell OS. Of the 28 cases, three (10.7%) were low grade, and 25 (89.3%) were high grade. Thirteen patients had intralesional surgery, and 13 had marginal surgery as their initial treatment. Recurrence was the rule in the first group, and it was 69% in the second group. Twenty patients (71%) died, and eight are alive. Of these, two are alive with disease. In the six patients who are alive and disease-free, all but one had marginal to wide surgical margins at the time of the first procedure or wide margins at the time of the recurrences along with chemotherapy or radiation therapy. In the patient in which the surgical margins were marginal, the lesion was small 2.5 X 2 cm. This patient was alive without evidence of disease after 9 years of follow-up.  相似文献   
994.
995.
Personality of patients with pseudoseizures   总被引:7,自引:0,他引:7  
We studied personality features of 19 patients with pseudoseizures (PS) only. Scores on a personality inventory (MMPI) were compared with those of adults with generalized seizures and correlated to cognitive measures (Halstead-Reitan). Mean MMPI scores did not differ significantly, and no profile distinguished PS and epilepsy patients. MMPI abnormalities of PS patients were diverse and seldom characteristic of hysteria. Eight PS patients had cognitive impairment, two without MMPI evidence of personality disorder. These findings suggest that the etiology of pseudoseizures is multifactorial, involving different psychopathologies and sometimes cerebral dysfunction.  相似文献   
996.
Abnormal pressor responses are known to occur in the maternal circulation in pregnancy-induced hypertension (PIH), but little is know of the response of the foetal circulation. The responsiveness of umbilical arteries in PIH can be studied after delivery, and this is a useful model to explore the pathophysiological mechanisms involved. In the present experiments, the in vitro response of umbilical artery rings to bradykinin and 5-hydroxytryptamine (5-HT) was tested and ultrastructural changes investigated. Umbilical arteries from 48 cords were studied. Fifteen of the mothers had PIH, five had essential hypertension pre-dating the pregnancy and five had diabetes. Twenty-three women had pregnancies uncomplicated by hypertension or serious medical or obstetric problems and these served as controls. Umbilical arteries from the severe proteinuric PIH group were significantly more responsive to 5-HT as assessed by affinity constants (P less than 0.05). The responsiveness of arteries from all other groups did not differ from the normal cases. A probable mechanism for the findings is endothelial damage as a result of pre-eclamptic disease. This was substantiated by ultrastructural evidence.  相似文献   
997.
Tests of orientation, concentration and shortterm visual memorywere used to assess 72 patients 1 day before, and 2 days after,elective major surgery. Patients were premedicated with papaveretumand either atropine or glycopyrrolate, before receiving a standardgeneral anaesthetic. Those who had received atropine showedsignificant postoperative short-term memory deficit (P< 0.01),but no change in orientation or concentration. Those who hadbeen given glycopyrrolate showed no significant cognitive changesafter surgery. As glycopyrrolate does not cross the blood-brainbarrier freely, these findings support the involvement of centralcholinergic mechanisms in the deterioration of cognitive functionin the postoperative period.  相似文献   
998.
A 14-year-old junior high school boy was admitted to our institute. Previously he had been diagnosed as having peripheral pulmonary stenosis (Gay's classification, type IV) at the age of 2 years and 10 months. On this occasion, however, a diagnosis of supravalvular aortic stenosis was made, with a pressure gradient of about 120 mmHg, and all examinations showed spontaneous remission of peripheral pulmonary stenosis. He underwent a successful standard aortoplasty. This is the first reported case of spontaneous remission of peripheral pulmonary stenosis.  相似文献   
999.
Cystatin C, alias post-gamma-globulin or gamma-trace protein, has been shown to be a potent inhibitor of cysteine proteinases; this protein is normally present in different biological fluids, but particularly so in cerebrospinal fluid. The concentration of cystatin C was determined by radial immunodiffusion in cerebrospinal fluid from patients affected with multiple sclerosis, patients affected with various neurological diseases and in controls; it was also determined in brain tissue from 2 patients affected with multiple sclerosis and 3 control brains. Cystatin C cerebrospinal fluid levels were undetectable or depressed in many multiple sclerosis cases and the median value differed significantly from the control one. Its low concentration in multiple sclerosis suggests that the regulation of cysteine proteinases is impaired in this disease; hence enhanced activity of cysteine proteinases could initiate, or increase the breakdown of myelin. Although it is perhaps a little premature to consider cystatin C as a marker for multiple sclerosis, this protein is nevertheless associated to demyelination; consequently its biochemical assay in cerebrospinal fluid is recommended as a complementary diagnostic tool.  相似文献   
1000.
Unilateral pseudobulbar syndrome with limited capsulothalamic infarction   总被引:5,自引:0,他引:5  
A unilateral pseudobulbar syndrome consequent to unilateral capsulothalamic infarction is described. Motor deficit of the face was associated with marked velar and pharyngeal unilateral palsy; paresis of limbs was mild. ACT scan revealed a circumscribed infarction of the genu of the internal capsule. This raised the problem of unilateral supranuclear pharyngeal palsies and of the precise anatomy of the genicular tract in the genu of the internal capsule.  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