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   25299篇
  免费   1907篇
  国内免费   748篇
耳鼻咽喉   1524篇
儿科学   272篇
妇产科学   193篇
基础医学   1033篇
口腔科学   435篇
临床医学   3902篇
内科学   1091篇
皮肤病学   125篇
神经病学   369篇
特种医学   1097篇
外科学   1043篇
综合类   9713篇
现状与发展   2篇
一般理论   10篇
预防医学   3033篇
眼科学   174篇
药学   1572篇
  683篇
中国医学   1480篇
肿瘤学   203篇
  2024年   100篇
  2023年   394篇
  2022年   932篇
  2021年   1219篇
  2020年   1239篇
  2019年   653篇
  2018年   580篇
  2017年   645篇
  2016年   716篇
  2015年   744篇
  2014年   2024篇
  2013年   1694篇
  2012年   1865篇
  2011年   2089篇
  2010年   1811篇
  2009年   1565篇
  2008年   1687篇
  2007年   1635篇
  2006年   1455篇
  2005年   1002篇
  2004年   696篇
  2003年   533篇
  2002年   353篇
  2001年   319篇
  2000年   264篇
  1999年   220篇
  1998年   171篇
  1997年   177篇
  1996年   133篇
  1995年   114篇
  1994年   156篇
  1993年   92篇
  1992年   101篇
  1991年   68篇
  1990年   71篇
  1989年   52篇
  1988年   62篇
  1987年   38篇
  1986年   32篇
  1985年   47篇
  1984年   40篇
  1983年   26篇
  1982年   39篇
  1981年   23篇
  1980年   16篇
  1979年   14篇
  1978年   19篇
  1977年   8篇
  1976年   8篇
  1975年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
图表比较教学法在微生物学教学中的应用   总被引:1,自引:0,他引:1  
图表比较教学法作为微生物学教学的直观教学手段在本科教学中占有十分重要的地位,是形象思维和抽象思维两种思维方式的协调统一。有利于反映各知识层面的内在联系,可使学生加深对知识的理解,增强分析和综合问题的能力,以利于提高教学质量。  相似文献   
32.
Serum IgA and IgG functional antibodies and their subclasses to Streptococcus pneumoniae capsular antigen found in two aged‐matched cohorts of children with and without otitis media with effusion The relationship between acute otitis media and otitis media with effusion (OME) is uncertain and the aetiology of OME is multifactorial. Otitis media with effusion may be an inflammatory condition; both bacteria and viral infections could play a part in this inflammation. The four bacteria Streptococcus pneumoniae, Haemophilus influenza, Staphylococcus aureus and Branhamella catarrhalis cause 60% of the infections whereas S. pneumoniae accounts for up to 35%. IgA provides the dominant surface response to polysaccharide and lipopolysaccharide antigens, of which IgA2 is the main subclass. Once the mucosa has been breached, most protection is provided by IgG. IgG2 acts mainly against bacterial capsular antigens. This study looked at two groups of 50 children with and without OME who were aged between 3 and 10 years. The aims were to determine if, firstly, the levels of the serum immunoglobulins were different in the two groups, secondly whether these children made the appropriate antibody response to the capsular antigen to S. pneumoniae (PCP), and finally if there was a delay in the maturity of the IgA response. The total IgG, IgA and all subclass levels were measured using radial immunodiffusion. Levels of functional IgA and IgG were measured using ELISAs (25 patients in each group). The results were analysed with non‐parametric tests. The immunoglobulin levels were within the normal levels for both groups. There were very good correlations between the IgG total anti‐PCP and the IgG2 anti‐PCP (R > 0.9, p = 0.001). There was a good correlation between the levels of both IgG total and IgG2 anti‐PCP against IgA total anti‐PCP in both groups (R > 0.85, p > 0.01). This confirms a normal antibody response between both groups of patients. The ages of the controls and patients (50 samples) were correlated with increasing titres of circulating functional antibodies (P = 0.001). This is highly suggestive of a normal age‐related response. In conclusion, the findings were contradictory to our original hypothesis that there is a subtle difference in surface protection between children with and without OME. We believe that a previous history of recurrent acute otitis media is unrelated to the development of OME after 3 years of age.  相似文献   
33.
周文俊 《中医教育》2007,26(4):49-52
社会主义本质论本身比较抽象,加上现实与理论存在着较大差距,学生思想认识问题较多,使得社会主义本质论的教学难以得取得实效。针对这一实际,提出了从历史和现实2个方面激发学生的学习兴趣,用"定义法"和"比较法"讲清"什么是社会主义",从理论和实践两个层面解决学生思想认识问题的教学策略,为提高教学实效探索了一条有效途径。  相似文献   
34.
网络教育资源构建中Windows Media流媒体技术的应用与研究   总被引:1,自引:0,他引:1  
Windows Media流媒体由于交互性强、使用方便和效率高,使得在网络教育中的应用逐渐增多。本文讨论了Windows Media流媒体技术在网络教育和资源构建中应用的优势及其在设计、制作、发布、应用等各环节的相关理论和技术细节。  相似文献   
35.
We present a patient who developed a painful third nerve galsy two days after angiography had demonstrated a large aneurysm on the P1 segment of the left posterior cerebral artery. CT at this stage demonstrated extensive thrombus within the previously uncomplicated aneurysm. The haemodynamics of this aneurysm resulted in incomplete clearance of contrast medium from its fundus and we posit that this may have promoted thrombus formation. Six months later the aneurysm was shown angiographically to be completely occluded.  相似文献   
36.
Students teaching students: a medical school peer tutorial programme   总被引:1,自引:0,他引:1  
A peer tutorial programme which is available to all first- and second-year medical students has been in operation at Case Western Reserve University School of Medicine since 1972. A retrospective study of the classes of 1982, 1983 and 1984 was undertaken to assess the participation levels in the tutorial programme and to compare the participation level to available performance parameters. The analysis revealed that 54% of the first-year classes and 22% of the second-year classes participated in the peer tutorial programme. X2 analysis of the data demonstrated that the relationship between participation in the tutorial programme and performance on examinations reached statistical significance. The results suggested that an open peer tutorial programme responded to the needs, both cognitive and affective, of medical students.  相似文献   
37.
This paper describes a teaching programme for final- (sixth-) year undergraduate medical students during their 10-week term in child health. Students attend schools on two occasions and are actively involved in the physical, educational and emotional assessment of children. The advantages of the programme include active participation by the students, contact with children in a less threatening environment, learning new skills in the assessment of children, and knowledge of common screening procedures. Student evaluation of the programme has been positive.  相似文献   
38.
The authors describe their preliminary experience with the use of superparamagnetic magnetic resonance (MR) imaging contrast media for suppression of signal from flowing blood. The goal of this work was to determine if a superparamagnetic contrast agent could successfully eliminate blood signal during cardiac-gated MR imaging, thereby eliminating or reducing flow artifacts associated with the complex and variable hemodynamics within the heart chambers. Imaging and data analysis were performed in 17 dogs subjected to experimental myocardial infarction as part of a parallel project. Six doses (0.2, 1, 2, 3.5, 4, 5, and 10 mg/kg) of AMI-25, an experimental contrast agent, were used in the study. Spin-echo imaging was performed immediately before and every 5 minutes (for an average of 25 minutes) after bolus injection of the contrast agent. Variations in the image signal-to-noise ratio relative to a baseline (before injection of contrast agent) image were assessed as a function of dose and time. Preliminary results suggest that a considerable reduction in blood flow artifacts and, hence, increases in image signal-tonoise ratio can be achieved at doses greater than or equal to 3.5 mg/kg, for approximately 20 minutes after injection. Doses equal to or less than 2 mg/kg and images obtained more than 20 minutes after injection (regardless of dose) did not reliably show hemodynamic artifact suppression.  相似文献   
39.
Purpose The goal of the study is to evaluate utility of contrast enhanced ultrasound (US) with carbon dioxide microbubbles in evaluation of hepatic lesions.Methods Twenty eight patients with single or multiple t hepatic lesions (11 hepatocellular carcinoma, 8 hemangiomas, 5 metastases, 1 adenoma, 1 focal nodular hyperplasia, 2 regenerative nodules) were examined. US exam was performed during intraarterial injection of 10 ml of CO2 through the same catheter employed for liver arteriography. The US exam was videotaped in its salient phases. Characteristics of enhancement were evaluated and correlated with histological findings or patient follow up.Results Sonographic angiography clearly demonstrated vascularization of the lesions. Hepatocellular carcinoma, hemangioma, metastases, focal nodular hyperplasia, and regenerative nodules had very characteristic patterns. The injection of CO2 allowed detection of small additional nodules.Conclusion Sonographic angiography can improve characterization and staging of hepatic tumors. Low cost and the simplicity of the technique should encourage further experimentation.  相似文献   
40.
谈多媒体教学在医学理论课教学中的问题及措施   总被引:28,自引:3,他引:25  
多媒体技术在教育领域的应用,促进了教育教学理念和方式的变革。然而,通过调查,在医学理论课多媒体教学中出现了一些问题,寻找解决问题的出路,是促进多媒体教学不断成熟和完善,提高现代化教学手段质量的最佳途径。  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