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   285篇
  免费   18篇
  国内免费   49篇
儿科学   2篇
妇产科学   2篇
基础医学   31篇
口腔科学   1篇
临床医学   48篇
内科学   143篇
皮肤病学   3篇
神经病学   12篇
特种医学   22篇
外科学   6篇
综合类   7篇
预防医学   13篇
药学   46篇
肿瘤学   16篇
  2021年   2篇
  2020年   1篇
  2019年   1篇
  2018年   2篇
  2017年   4篇
  2015年   13篇
  2014年   6篇
  2013年   6篇
  2012年   6篇
  2011年   7篇
  2010年   5篇
  2009年   4篇
  2008年   5篇
  2007年   38篇
  2006年   5篇
  2005年   13篇
  2004年   8篇
  2003年   10篇
  2002年   9篇
  2001年   7篇
  2000年   13篇
  1999年   16篇
  1998年   15篇
  1997年   10篇
  1996年   15篇
  1995年   11篇
  1994年   6篇
  1993年   4篇
  1992年   12篇
  1991年   7篇
  1990年   4篇
  1989年   10篇
  1988年   18篇
  1987年   11篇
  1986年   17篇
  1985年   3篇
  1984年   2篇
  1983年   2篇
  1982年   3篇
  1981年   3篇
  1980年   4篇
  1979年   1篇
  1978年   1篇
  1977年   3篇
  1974年   3篇
  1972年   1篇
  1967年   1篇
  1966年   1篇
  1962年   1篇
  1959年   1篇
排序方式: 共有352条查询结果,搜索用时 187 毫秒
1.
Delta hepatitis virus infection in China   总被引:1,自引:0,他引:1  
To assess the prevalence, epidemiological features and prognostic implications of hepatitis D (Delta) in Sichuan Province, The People's Republic of China, 649 sera (515 from HBsAg positive patients and 134 from HBsAg negative subjects) were tested by radioimmunoassay (RIA) for antibody to the hepatitis D virus (anti-HD). Forty-seven sera (7.2%) showed some degree of reactivity. Serial dilutions of these sera indicated that prozoning was not responsible for the equivocal results. Thirty-four of the 47 sera were submitted under code to a second laboratory for independent analysis. According to those results anti-HD antibodies were detected in four of these sera. The overall prevalence of anti-HD in the HBsAg positive patients therefore was 0.8% (4/515). On the basis of clinical, biochemical and histological data 427 HBsAg positive sera were further divided into acute Type B hepatitis, chronic Type B hepatitis, healthy carrier state and hepatocellular carcinoma (HCC) subgroups. Two of 65 (3.1%) anti-HD positive sera belonged to the acute Type B hepatitis group; one of 104 (0.9%), the chronic Type B hepatitis group and one of 246 (0.4%), the healthy carrier group. No antibody was detected in sera from 12 HBsAg positive HCC patients. All HBsAg negative patients were negative for anti-HD antibody. The results of this study indicate that despite a high prevalence of hepatitis B virus infection, positive serology for delta virus is uncommon in Sichuan Province, The People's Republic of China.  相似文献   
2.
Dural sinus thrombosis: study using intermediate field strength MR imaging   总被引:1,自引:0,他引:1  
The magnetic resonance (MR) images of six patients with thrombosis of a dural sinus were reviewed. The diagnosis had been verified by computed tomographic scans in three patients and arteriograms in two; in the sixth patient, only MR imaging was used to confirm the clinical syndrome. In all patients, high-intensity signal was seen from the thrombus within the affected dural sinus on all echoes. This persistent signal intensity allowed intravascular clot to be distinguished from normal causes of increased signal such as flow-related enhancement (entry phenomenon) and even-echo rephasing. MR imaging demonstrated the cause of the thrombosis in three patients: two were secondary to adjacent tumors, and one was secondary to unsuspected mastoiditis. Complications such as infarction were also demonstrated. Using MR imaging, one can easily and safely diagnose thrombosis of a dural sinus. MR should be the imaging method of choice in patients suspected of having thrombosis of a dural sinus.  相似文献   
3.
We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder.  相似文献   
4.
Impact of clinical history on fracture detection with radiography   总被引:3,自引:0,他引:3  
The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information.  相似文献   
5.
The effect of H1 and H2 receptor-blocking agents on antibody-dependent cell-mediated cytotoxicity (ADCC) was studied. The H1 receptor-blocker clemastinum and the H2 receptor blocker cimetidine dose-dependently inhibited the antibody-dependent cytotoxic activity of normal human peripheral blood mononuclear cells on chicken erythrocytes. The inhibition cannot be explained either by a direct toxic effect on effector cells or by blocking of Fc receptors. The possible involvement of histamine receptor-bearing effector cells in human ADCC is suggested.  相似文献   
6.
For 75 patients with systemic lupus erythematosus (SLE), 39 laboratory and clinical characteristics, including HLA-A, B, C and DR typing, were analysed using a cluster analysis technique. Three groups were identified. Group I (46 patients) was characterized by infrequently severe disease, good response to therapy and infrequent multisystem involvement. Group I1 (24 patients) was characterized by a severe course of disease (although the tendency to remit after therapy was not unusual), and, frequently, renal involvement and pericarditis. Group 111 (5 patients) was characterized by more severe renal disease. Of the 75 patients studied, 38.7% possessed HLA-DR3, compared to 17.4% of controls. Group I patients did not differ from controls but 80% of Group II patients and 4/5 Group III patients had DR3. Cluster analysis identifies subsets of SLE patients who show marked differences in disease course and severity, correlated with possession of the HLA B8, DR3 phenotype.  相似文献   
7.
Summary The venous architecture in donor flaps was observed in 17 fresh cadavers by injection of latex or ink into the vessels or by making corrosion-cast specimens. The pattern of the veins resembles that of the arteries, with the difference that there is another set of venous trunks which do not accompany the arteries. Because these trunks are of larger caliber, they are the main drainage route for flaps. There are three types of drainage based on the anatomical architecture: 1) the superficial trunk is the main drainage path; 2) the deep trunk is the main path; 3) both superficial and deep veins are involved. These morphological considerations are the basis for selection of veins for anastomosis in microsurgery. The axial veins in temporal, frontal and facial flaps on the dorsum of the hand and the foot usually loosely accompany the axial arteries. The characteristics of these vascular pedicules should be studied in transplant operation.
Bases anatomiques du drainage veineux des lambeaux cutanés libres
Résumé Le drainage veineux des lambeaux cutanés libres a été étudié sur 17 cadavres frais par injection de latex ou d'encre dans les vaisseaux, ou en réalisant des moulages par injection-corrosion. La distribution des veines ressemble à celle des artères à la différence près qu'il existe des troncs veineux qui n'accompagnent pas les artères. Ces troncs ont un calibre plus important et représentent une voie de drainage principale pour les lambeaux. On peut individualiser trois types de drainages basés sur l'architecture veineuse : 1. Le tronc superficiel est la principale voie de drainage ; 2. le tronc profond est la principale voie; 3. les veines superficielles et profondes sont impliquées simultanément. Ces considérations morphologiques sont les bases de la sélection des axes veineux pour les anastomoses en micro-chirurgie. Les veines axiales au niveau temporal, frontal et facial et pour les lambeaux de la face dorsale de la main et du pied sont habituellement relativement éloignées du trajet artériel. Les caractéristiques de ces pédicules veineux doivent être précisées pour la réalisation des lambeaux.
  相似文献   
8.
The hammerhead ribozyme is a small catalytic RNA molecule. Potential hammerhead ribozymes that possess a catalytic domain and flanking sequence complementary to a target mRNA can cleave in trans at a putative cleavage site within the target molecule. We have investigated the potential of hammerhead ribozymes to down-regulate the product of the fibrillin-1 gene (FBN1). Fibrillin is a 347 kDa glycoprotein that is a major constituent of the elastin-associated microfibrils. Mutations in the FBN1 gene are responsible for Marfan syndrome (MFS), a common systemic disorder of the connective tissue. Many FBN1 mutations responsible for MFS appear to act in a dominant-negative fashion, raising the possibility that reduction of the amount of product from the mutant FBN1 allele might be a valid therapeutic approach for MFS. A trans-acting hammerhead ribozyme (FBN1-RZ1) targeted to the 5' end of the human FBN1 mRNA has been designed and synthesized, and shown to cleave its target efficiently in vitro. FBN1-RZ1 cleavage is magnesium dependent and efficient at both 37 and 50 degrees C. Delivery of the FBN1-RZ1 ribozyme into cultured dermal fibroblasts, by receptor- mediated endocytosis of a ribozyme-transferrin-polylysine complex, specifically reduces both cellular FBN1 mRNA and the deposition of fibrillin in the extracellular matrix. These results suggest that the use of hammerhead ribozymes is a valid approach to the study of fibrillin gene expression and possibly to the development of a therapeutic approach to MFS.   相似文献   
9.
A 71-yr-old man with a six-year history of Parkinson’s disease (PD), Type II diabetes mellitus, myocardial infarction, and remote 20 pack-year smoking history, underwent an anterior resection of the rectum for carcinoma. Sixty hours later, the patient suffered a respiratory arrest; his antiparkinsonian medications had not been resumed. Preoperative flow-volume loops showed the characteristic saw-tooth pattern of PD indicating dysfunction of the striated muscle of the upper airway. Although postoperative respiratory distress was managed as lower airway obstruction, at the time of intubation there were no signs of lower airway pathology. Upper airway dysfunction and obstruction secondary to PD is thought to have been a contributing factor to the postoperative respiratory distress and failure. This case is presented to draw attention to the risk of upper airway dysfunction in Parkinson’s Disease, especially with the withdrawal of antiparkinsonian medications. Un homme de 71 ans souffrant d’une maladie de Parkinson depuis six ans, de diabète type II, d’un infarctus du myocarde avec une histoire de tabagisme de 20 années-paquet, subit une résection antérieure du rectum pour un cancer. Soixante heures plus tard, il fait un arrêt respiratoire avant d’avoir recommencé sa médication antiparkinsonnienne. Les courbes débits-volumes préopératoires montraient un tracé en dents de scie caractéristique du dysfonctionnement des muscles striés des voies aériennes supérieures consécutif au parkinsonnisme. Bien que cette détresse postopératoire ait été traitée comme une obstruction des voies aériennes inférieures, on n’a pas observé de signes de cette pathologie à l’intubation. On emit que le dysfonctionnement de voies aériennes supérieures a surtout contribué à la détresse et à l’insuffisance respiratoires postopératoires. Cette observation est présentée dans le but d’attirer l’attention sur le risque de dysfonctionnement des voies respiratoires causé par la maladie de Parkinson, particulièrement après l’arrêt de la médication spécifique.  相似文献   
10.
Hepatitis B infection is endemic in many parts of the world, including Korea. Basic knowledge of the hepatitis B virus by the public is a prerequisite for the development of a successful vaccination program. A survey was conducted in rural Korea to examine public knowledge of hepatitis B etiology, symptoms, transmission, risk factors and prevention. It was found that knowledge independently correlated with education and female sex, but that overall knowledge of hepatitis B was poor. The preferred information sources in order of preference were physicians, television and public health nurses. This information may be useful in designing public health education and vaccination programs in developing populations.  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