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   1348965篇
  免费   94843篇
  国内免费   2977篇
耳鼻咽喉   19886篇
儿科学   40463篇
妇产科学   38792篇
基础医学   188877篇
口腔科学   40226篇
临床医学   113448篇
内科学   265429篇
皮肤病学   30374篇
神经病学   107399篇
特种医学   54241篇
外国民族医学   435篇
外科学   210476篇
综合类   31098篇
现状与发展   6篇
一般理论   436篇
预防医学   92495篇
眼科学   31535篇
药学   100874篇
  4篇
中国医学   3006篇
肿瘤学   77285篇
  2018年   11995篇
  2015年   12097篇
  2014年   17014篇
  2013年   25632篇
  2012年   33636篇
  2011年   35513篇
  2010年   21153篇
  2009年   20602篇
  2008年   34193篇
  2007年   37306篇
  2006年   37908篇
  2005年   36682篇
  2004年   35726篇
  2003年   34705篇
  2002年   34257篇
  2001年   64026篇
  2000年   65715篇
  1999年   55779篇
  1998年   14849篇
  1997年   13604篇
  1996年   13076篇
  1995年   12321篇
  1994年   11554篇
  1992年   42991篇
  1991年   41484篇
  1990年   40752篇
  1989年   39790篇
  1988年   37171篇
  1987年   36591篇
  1986年   35078篇
  1985年   33257篇
  1984年   24945篇
  1983年   21147篇
  1982年   12717篇
  1981年   11615篇
  1980年   10814篇
  1979年   24005篇
  1978年   17130篇
  1977年   14896篇
  1976年   13425篇
  1975年   15318篇
  1974年   18138篇
  1973年   17615篇
  1972年   16860篇
  1971年   15764篇
  1970年   14961篇
  1969年   14408篇
  1968年   13503篇
  1967年   12067篇
  1966年   11306篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Complex regional pain syndrome (CRPS) was formerly known as “Sudeck’s atrophy”. The disease belongs to the group of neuropathic pain syndromes and is differentiated into three types. Type I is characterized by a lack of nerve lesions, type II by the presence of nerve lesions, and type III by the presence of other entities such as fibromyalgia. The exact pathogenic factors leading to the disease are still unknown and are currently the subject of investigation in various studies. These studies suggest a contribution of the central nervous system to the development and maintenance of CRPS. However, the clinical symptoms are well documented and include pain, autonomic changes and impaired motor function of the affected extremity. Diagnosis is based clinically on signs and symptoms. However, in a few cases radiography and scintiscanning may be useful to finalize the diagnosis. The treatment options are centred on the symptoms of pain, autonomic changes and functional impairment. A multidisciplinary treatment strategy is recommended, with surgeons, anaesthesiologists, physiotherapists and psychotherapists working together. Surgical intervention in this disease is only required in rare cases of neurological and bone pain, and the indications for such intervention are narrow and should be strictly observed.  相似文献   
82.
Severe adverse effects during the use of ovulation inhibitors occur mostly in women who have an elevated risk for the development of certain diseases owing to hereditary or acquired factors. By means of a careful personal or family history analysis as well as specific laboratory examinations, an existing predisposition may frequently be diagnosed and the individual risk associated with the use of oral contraceptive inhibitors may be estimated. The present contribution describes the potential effects of treatment with ovulation inhibitors on women with thrombophilia, cardiovascular disease, diabetes mellitus, dyslipidemia, overweight or underweight, tumors, psychiatric and neurological diseases and autoimmune disease. The hormonal methods and non-hormonal alternatives available for contraception are elucidated according to existing lesions and risk factors and the advantages and disadvantages are discussed.  相似文献   
83.
Introduction The associations between vitamin D receptor (VDR) Bsm I and Fok I genotypes, parity, and risk of osteoporotic hip fracture were evaluated in a statewide population-based case-control study in Utah.Methods Women age 50–89 years with hip fracture (n=882) were ascertained via surveillance of 18 Utah hospitals from 1997 to 2001. Age-matched controls were randomly selected (n=897). Participants were interviewed in their homes, and blood samples were collected for genotyping.Results In logistic regression analyses that controlled for multiple confounders, Bsm I VDR genotype but not Fok I genotype was associated with risk of osteoporotic hip fracture (OR bb vs. BB genotype: 0.68; 95% CI: 0.50, 0.95). In similar analyses, no overall association was observed between parity status and risk of osteoporotic hip fracture. However, the effect of VDR genotype was modified by parity status. Among nulliparous women (n=140), Bsm I genotype was not associated with risk of hip fracture (OR bb vs. BB: 0.82; 95% CI: 0.28, 2.4); among primiparous women (n=133), bb genotype was associated with increased risk of hip fracture (OR bb vs. BB: 3.30; 95% CI: 0.96, 11.29); among multiparous women (n=1,400), bb genotype was associated with decreased risk of hip fracture (OR bb vs. BB: 0.59; 95% CI: 0.42, 0.84).Conclusion VDR Bsm I genotype was associated with risk of hip fracture in Utah women, and this effect was modified by parity status. Hormonal or lifestyle factors related to parity may underlie this interaction.  相似文献   
84.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  相似文献   
85.
86.
87.
88.
89.
Abstract Chorea is a rare complication of polycythaemia vera. Polycythaemic chorea occurs predominantly in females and usually in generalised form. We present a 66-year-old woman with acute onset hemichorea-ballism with no vascular pathology in the basal ganglia region. A clear relationship was observed between the onset of chorea and worsening of haematological parameters in the patient. After repeated phlebotomies the patient's clinical status was improved. Polycythaemic chorea must be considered, especially in the elderly, as early diagnosis leads to effective treatment and prevention of complications.  相似文献   
90.
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