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   25178篇
  免费   2199篇
  国内免费   483篇
耳鼻咽喉   220篇
儿科学   302篇
妇产科学   663篇
基础医学   2478篇
口腔科学   198篇
临床医学   2505篇
内科学   3764篇
皮肤病学   237篇
神经病学   736篇
特种医学   659篇
外科学   2460篇
综合类   2163篇
一般理论   2篇
预防医学   1823篇
眼科学   126篇
药学   1823篇
  10篇
中国医学   471篇
肿瘤学   7220篇
  2023年   531篇
  2022年   1058篇
  2021年   1392篇
  2020年   1098篇
  2019年   1761篇
  2018年   1725篇
  2017年   1322篇
  2016年   906篇
  2015年   959篇
  2014年   2098篇
  2013年   1878篇
  2012年   1339篇
  2011年   1505篇
  2010年   1104篇
  2009年   1066篇
  2008年   1256篇
  2007年   1028篇
  2006年   780篇
  2005年   642篇
  2004年   562篇
  2003年   427篇
  2002年   261篇
  2001年   274篇
  2000年   242篇
  1999年   238篇
  1998年   194篇
  1997年   179篇
  1996年   187篇
  1995年   152篇
  1994年   150篇
  1993年   108篇
  1992年   73篇
  1991年   62篇
  1990年   51篇
  1989年   64篇
  1988年   43篇
  1987年   43篇
  1986年   34篇
  1985年   129篇
  1984年   137篇
  1983年   117篇
  1982年   143篇
  1981年   110篇
  1980年   92篇
  1979年   88篇
  1978年   53篇
  1977年   41篇
  1976年   39篇
  1975年   32篇
  1974年   33篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
用参与建立数学模型的521例资料和307例没参与建立数学模型的病例资料验证电子计算机监护慢性肝病的程序。以病理学检查、或以3个月至3年的临床观察结果作为诊断的金标准。254例临床诊断作为对照。验证结果表明(1)计算机监护优于临床诊断,(2)本程序敏感度高。  相似文献   
32.
This paper reviews the literature on colorectal cancer from a sex and gender-based perspective. Colorectal cancer is a major cause of death in the developed world, with rates increasing in developing countries. Although described by some writers as an ‘equal opportunity’ disease, it presents more risk to men than women. Both biological, or sex-linked factors, and gender-linked factors play a part in the aetiology of the disease, while gender differences in the use of screening and treatment also help shape the mortality gap between women and men for this condition. Without an appreciation of the part played by sex and gender in the risk of colorectal cancer, and without a gender-sensitive approach to screening in particular, it is possible that the mortality gap between men and women for this condition will widen in the future.  相似文献   
33.
Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is mainly observed in patients with multiple myeloma and bone metastasis from solid tumors receiving iv bisphosphonate therapy. The reported incidence of BRONJ is significantly higher with the iv preparations zoledronic acid and pamidronate while the risk appears to be minimal for patients receiving oral bisphosphonates. Currently available published incidence data for BRONJ are based on retrospective studies and estimates of cumulative incidence range from 0.8 to 12%. The mandible is more commonly affected than the maxilla (2:1 ratio), and 60–70% of cases are preceded by a dental surgical procedure. The signs and symptoms that may occur before the appearance of clinical evident osteonecrosis include changes in the health of periodontal tissues, non-healing mucosal ulcers, loose teeth and unexplained soft-tissue infection. Although the definitive role of bisphosphonates remains to be elucidated, the inhibition of physiologic bone remodeling and angiogenesis by these potent drugs impairs the regenerative capacity of the bone causing the development of BRONJ. Tooth extraction as a precipitating event is a common observation. The significant benefits that bisphosphonates offer to patients clearly surpass the risk of potential side effects; however, any patient for whom prolonged bisphosphonate therapy is indicated, should be provided with preventive dental care in order to minimize the risk of developing this severe condition. This article provides an update review of current knowledge about clinical, pathological and management aspects of BRONJ.  相似文献   
34.
Chronic motor cortex stimulation is a treatment option for neuropathic drug-resistant pain and possibly associated movement disorders. Preliminary studies suggest the possibility to treat symptoms of Parkinson disease in selected patients. Recently, MCS has been suggested to enhance motor recovery in patients with poststroke hemiparesis. One or more electrodes are placed extradurally over the motor cortex through a burr hole or a small craniotomy, and then connected to a totally implantable neurostimulator. The accurate positioning of the stimulating electrodes over the motor cortex is the key point of the surgical procedure. Motor cortex identification results from the integration of anatomical, neuroradiological, functional, and neurophysiological data, taking into account the huge population variability. Intraoperative neurophysiological mapping of the motor cortex is of paramount importance, in spite of very sophisticated neuroradiological mathematical reconstructions of the motor area. We discuss and compare the different techniques that are utilized by different authors. Moreover, clinical neurophysiology is also helpful in evaluating the results of this neuromodulation procedure and in hypothesizing the mechanisms that are put in play by MCS.  相似文献   
35.
36.
The role of acquired chromosomal rearrangements in oncogenesis (cytogenomics) and tumor progression is now well established. These alterations are multiple and diverse and the products of these rearranged genes play an essential role in the transformation and growth of cancer cells. The validity of this assumption is demonstrated by the development of specific inhibitors or antibodies that eliminate tumoral cells by targeting some of these changes. Imatinib, an inhibitor of the tyrosine kinase ABL, the prototype of these targeting drugs, is yielding complete remissions in most CML patients. Knowledge of chromosomal abnormalities is becoming an essential contribution to the diagnosis and prognosis of cancers but also for monitoring minimal residual disease or relapse. The concept of the “cytogenetic uniqueness” of each cancer has resulted in personalized treatment. This investigation will expound upon, besides the recurrent genomic alterations, the numerous products of perverted Darwinian selection at the cellular level.  相似文献   
37.
Mortality rate of gastric cancer in Japan had been the highest in the world. Development of early detection and effective treatment was the most impor-tant social demand. For the early detection, Japan de-veloped “double contrast X-ray”, “endoscopy and en-doscopic biopsy”, and “mass screening system”. The Japanese nationwide registry collected data of 273,142 gastric cancer patients in the last 30 years. By the ef-forts of early detection, proportion of Stage I cancer increased from 22.5% to 58.1% in the registry. Cu-mulative 5 year survival rate of resected cases was improved from 37.5% (1962) to 68.8% (1991). Im-provement was remarkable for Stage-II; from 47.7% to 70.3%, and for Stage-III, from 26.4% to 45.0%.  相似文献   
38.
乳腺癌患者血中角蛋白mRNA基因的表达   总被引:1,自引:0,他引:1  
目的 分析乳腺癌患者外周血液中角蛋白(CK19)mRNA基因的表达。方法 取20例经病理证实的乳腺癌患者外周血,用Tirizol法提取总RNA,然后进行RT-PCR荧光定量检测,并与正常人群进行对照。结果 正常人群外周血中无CK19表达,20例乳腺癌中有6例阳性表达,总阳性率为29.65%,其中单纯癌阳性率为30.7%(4/13),浸润性导管癌阳性率为28.6%(2/7)。结论 CK19可作为检测外周血循环癌细胞的标志物。  相似文献   
39.
陈书盘  耿沁 《肿瘤》1997,17(5):258-261
目的评价检测CYFRA21┐1对非小细胞肺癌的诊断价值。方法用ELISA法测定70例肺癌(LC)其中47例非小细胞肺癌(NSCLC),3例小细胞肺癌(SCLC)和20例未分型肺癌、64例肺部良性疾病患者及40例健康人血清CYFRA21┐1浓度。试验的诊断性能用相对操作特征(ROC)分析法估测之。结果测得全阈诊断准确率(OveralDiag┐nosticAccuracies)LC为0.75、NSCLC为0.76,SQC为0.83,ADE为0.67和SCLC为0.38。在相应于特异性为0.95的界定值3.47μg/L处,各型的灵敏度分别为SQC0.62,LC0.53,NSCLC0.51,ADE0.48和SCLC0.00。结论结果显示CYFRA21┐1是NSCLC较灵敏和特异的一个标志物。未观察到TNM各期间该标志物的平均水平有明显的差异;然而异常升高水平的患者的比例随病期的进展而显著增加,提示一系列检测CYFRA21┐1水平可能有助于监查NSCLC患者的疗效。  相似文献   
40.
The purpose of this study was to evaluate the ability of MRI to identify a primary site of malignancy in the breast of patients who present clinically with ipsilateral lymph nodes containing metastatic carcinoma but whose physical and mammographic examination are negative. MRI of the breast was performed on four patients using a variety of imaging parameters, all with and without gadolinium contrast. All patients had biopsy-proven adenocarcinoma of the ipsilateral axilla, with negative physical and mammographic examinations. Foci of enhancement assessed visually on precontrast and postcontrast scans (n = 1) and on substraction studies (n = 3) were considered suspicious under the clinical circumstances defined for this study. Lesions identified on MRI were re-identified on ultrasound examination and either preoperative localization for excisional biopsy or tissue sampling was performed. Surgery was performed and histopathologic correlation was obtained in all cases. Primary sites of breast carcinoma were identified in all four patients, with multiple sites of malignancy identified in three of four patients. Breast conservation therapy was made possible for three of four patients based on the results of the MRI study showing sites of malignancy and no features of cancer elsewhere in the breast. Follow-up data of 1, 2, and 5 years of these patients show no evidence of recurrent disease. MRI of the breast is a useful technique for identifying primary sites of malignancy in patients presenting with ipsilateral lymph nodes positive for metastatic adenocarcinoma when the physical and mammographic examinations are negative.  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