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   2771篇
  免费   243篇
  国内免费   5篇
耳鼻咽喉   89篇
儿科学   202篇
妇产科学   50篇
基础医学   288篇
口腔科学   71篇
临床医学   255篇
内科学   578篇
皮肤病学   107篇
神经病学   204篇
特种医学   284篇
外科学   274篇
综合类   60篇
一般理论   2篇
预防医学   236篇
眼科学   48篇
药学   112篇
中国医学   1篇
肿瘤学   158篇
  2022年   21篇
  2021年   27篇
  2019年   21篇
  2018年   35篇
  2017年   25篇
  2016年   26篇
  2015年   36篇
  2014年   46篇
  2013年   66篇
  2012年   91篇
  2011年   101篇
  2010年   91篇
  2009年   91篇
  2008年   110篇
  2007年   132篇
  2006年   104篇
  2005年   100篇
  2004年   117篇
  2003年   97篇
  2002年   80篇
  2001年   100篇
  2000年   84篇
  1999年   62篇
  1998年   66篇
  1997年   89篇
  1996年   73篇
  1995年   59篇
  1994年   66篇
  1993年   64篇
  1992年   57篇
  1991年   53篇
  1990年   45篇
  1989年   68篇
  1988年   74篇
  1987年   56篇
  1986年   56篇
  1985年   58篇
  1984年   40篇
  1983年   41篇
  1982年   31篇
  1981年   34篇
  1980年   31篇
  1979年   23篇
  1978年   23篇
  1977年   27篇
  1976年   22篇
  1975年   25篇
  1974年   18篇
  1970年   22篇
  1965年   15篇
排序方式: 共有3019条查询结果,搜索用时 31 毫秒
951.
The retinoblastoma gene (Rb) is postulated to be important in carcinoma of the larynx. Its cellular protein (pRb) is involved in regulation of the cell cycle and may be influential in the cells response to irradiation injury. From the University of Liverpool Head and Neck Database we identified 35 patients with a T2 N0 laryngeal squamous carcinoma whom received primary irradiation and had a minimum of 5 years follow up. Laser capture microdissection was performed on paired normal and tumour biopsy material to analyse for loss of heterozygosity (LOH) and microsatelite instability (MI) of the Rb gene and immunohistochemistry (IHC) was carried out to detect pRb expression. Of 35 tumours, 13 were normal, 12 had MI and 5 had LOH of the Rb gene. Abnormalities at the Rb locus did not correlate with loss of pRb expression. There was also no significant difference between the distribution of normal and abnormal gene sequences and whether or not the primary laryngeal tumour recurred after radiotherapy. Rb gene abnormalities occurred in one third of T2 N0 laryngeal carcinomas. These were not in isolation predictive of cure by radiotherapy.  相似文献   
952.
953.
The hypoglossal nerve is an underrated nerve usually consigned to a few words in anatomical text books, under the last four cranial nerves. However, paralysis of this nerve may be the first indication of a serious underlying disorder. Excluding previous surgery, radiotherapy and trauma, 50 per cent of cases of isolated hypoglossal nerve palsy are idiopathic. A further 20 per cent are malignant, 20 per cent are vascular and 10 per cent are due to miscellaneous causes. Presentation of an isolated hypoglossal nerve palsy is therefore an ominous sign. There is confusion over both cause and investigation, and management protocols for isolated hypoglossal nerve palsy are ill-defined. We present a case of isolated hypoglossal palsy which was due to a metastatic skull base deposit. This case illustrates the fact that magnetic resonance imaging is the investigation of choice in assessing the entire course of the hypoglossal nerve.  相似文献   
954.
955.
The key principles of chronic heart failure and the development of clinical management strategies are described. The physiological changes in chronic heart failure and the clinical management of children with heart failure are considered, but the treatment of heart failure related to congenital heart disease or the intensive care management of heart failure are not mentioned as both topics require consideration in their own right. A greater understanding of the maladaptive responses to chronic heart failure has enabled targeted therapy to be introduced with consequent improvement in symptoms, reduction in hospitalisation and lower mortality.  相似文献   
956.
BACKGROUND: In England, screening for genital chlamydial infection has begun; however, screening frequency for women is not yet determined. AIM: To measure chlamydia incidence and reinfection rates among young women to suggest screening intervals. METHODS: An 18-month prospective cohort study of women aged 16-24 years recruited from general practices, family planning clinics and genitourinary medicine (GUM) clinics: baseline-negative women followed for incidence and baseline-positive women for reinfection; urine tested every 6 months via nucleic acid amplification; and behavioural data collected. Extra test and questionnaire completed 3 months after initial positive test. Factors associated with infection and reinfection investigated using Cox regression stratified by healthcare setting of recruitment. RESULTS: Chlamydia incidence was mean (95% CI) 4.9 (2.7 to 8.8) per 100 person-years (py) among women recruited from general practices, 6.4 (4.2 to 9.8) from family planning clinics and 10.6 (7.4 to 15.2) from GUM clinics. Incidence was associated with young age, history of chlamydial infection and acquisition of new sexual partners. If recently acquiring new partners, condom use at last sexual intercourse was independently associated with lower incidence. Chlamydia reinfection was mean (95% CI) 29.9 (19.7 to 45.4) per 100/person-year from general practices, 22.3 (15.6 to 31.8) from family planning clinics and 21.1 (14.3 to 30.9) from GUM clinics. Factors independently associated with higher reinfection rates were acquisition of new partners and failure to treat all partners. CONCLUSIONS: Sexual behaviours determined incidence and reinfection, regardless of healthcare setting. Our results suggest annual screening of women aged 16-24 years who are chlamydia negative, or sooner if partner change occurs. Rescreening chlamydia-positive women within 6 months of baseline infection may be sensible, especially if partner change occurs or all partners are not treated.  相似文献   
957.
958.
959.
Pseudohypoparathyroidism type la (PHP-1a) is an uncommon disorder that results from an inactivating mutation in the GNAS gene. It can present with resistance to several hormones, in addition to parathyroid hormone (PTH). Patients may have the classic Albright's hereditary osteodystrophy (AHO) phenotype and can develop resistance to thyroid stimulating hormone (TSH), gonadotropins, growth hormone releasing hormone (GHRH), and other hormones that rely on the Gsalpha protein to regulate signal transmission at their receptors. We report two siblings with PHP-1a and congenital hypothyroidism. The patients were found to have a heterozygous mutation at nucleotide 305 in exon 4 (c305C-->A) of the GNAS gene, which has not been previously linked to congenital hypothyroidism.  相似文献   
960.
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