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   46053篇
  免费   5072篇
  国内免费   104篇
耳鼻咽喉   641篇
儿科学   1351篇
妇产科学   1275篇
基础医学   7086篇
口腔科学   1094篇
临床医学   6176篇
内科学   8652篇
皮肤病学   622篇
神经病学   3641篇
特种医学   1649篇
外国民族医学   1篇
外科学   6088篇
综合类   1005篇
一般理论   29篇
预防医学   4742篇
眼科学   684篇
药学   3693篇
中国医学   64篇
肿瘤学   2736篇
  2021年   638篇
  2020年   424篇
  2019年   706篇
  2018年   820篇
  2017年   613篇
  2016年   754篇
  2015年   779篇
  2014年   1094篇
  2013年   1641篇
  2012年   2124篇
  2011年   2181篇
  2010年   1271篇
  2009年   1148篇
  2008年   1907篇
  2007年   2015篇
  2006年   1943篇
  2005年   1893篇
  2004年   1811篇
  2003年   1749篇
  2002年   1778篇
  2001年   1586篇
  2000年   1603篇
  1999年   1392篇
  1998年   686篇
  1997年   568篇
  1996年   487篇
  1995年   516篇
  1994年   481篇
  1993年   446篇
  1992年   1127篇
  1991年   1056篇
  1990年   1046篇
  1989年   969篇
  1988年   896篇
  1987年   912篇
  1986年   885篇
  1985年   902篇
  1984年   713篇
  1983年   613篇
  1982年   435篇
  1981年   352篇
  1980年   368篇
  1979年   582篇
  1978年   446篇
  1977年   366篇
  1976年   380篇
  1974年   379篇
  1973年   333篇
  1972年   338篇
  1971年   304篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
65.
66.
BACKGROUND. Latex agglutination (LA) tests are ordered frequently on cerebral spinal fluid (CSF) specimens obtained from pediatric patients to identify pathogenic bacteria as early as possible in an acute infection. METHODS. Six hundred ten LA tests were performed on 176 patients suspected of having meningitis. RESULTS. Five patients with meningitis had positive LA tests. We found that the CSF white blood cell (WBC) count, and differential were the best predictors of meningitis. CONCLUSIONS. By limiting the use of LA tests to those patients having CSF with abnormal WBC counts or with positive Gram stains, the number of tests ordered would have been reduced. This practice would greatly reduce laboratory expense.  相似文献   
67.
68.
The call for screening for an increasing number of surgical diseases is becoming louder and more frequent. There is a general perception that screening is ''good'' but it is important to consider the evidence carefully. There is one surgical disease that provides considerable experience of the process of screening over a period of 30 years and this is congenital dislocation of the hip (CDH). In retrospect, it is clear that screening for this disease has not been a total success. Although some specialised centres have achieved excellent results, in the country as a whole screening has been a failure. The reasons for this are analysed and emphasis is placed on the principles of screening which are briefly summarised. The results of various studies on screening and experiments on the basic functional anatomy of the neonatal hip are described. The initial results of our method of selective ultrasound screening appear to be encouraging and some evidence of a possible collagen abnormality in CDH is presented. As a general principle, however, it is suggested that strict randomised controlled trials should take place before national screening programmes are started.  相似文献   
69.
70.
OBJECTIVE To determine the long-term effects of external beam megavoltage radiotherapy (RT: 4500 cGy via three portals at 180 cGy or less total daily dose) on endocrine function in prolactinomas. DESIGN Longitudinal study following radiotherapy with periodic re-assessment at regular intervals, at least 2 months off dopamine agonist therapy. PATIENTS Thirty-six female patients, age range 19-50 years, with either macroprolactinomas (12 patients) or microprolactinomas (24 patients), but without significant suprasellar extensions. MEASUREMENTS Clinical appraisal, and anterior and posterior pituitary assessment: basal levels at yearly intervals or less, with dynamic screening with TRH, LHRH and hypoglycaemic stimulation every 2-3 years. RESULTS Before RT, serum prolactin (PRL) levels ranged from 1150 to 34,000 mU/l; after RT (mean 8.5 years, range 3-14), serum PRL fell to normal (i.e. less than 360 mU/l) in 18 of the 36 patients (50%), and to just above the normal range (378-780 mU/l) in a further 10 (28%). Two patients had PRL levels at their last follow-up higher than those at presentation, with one patient showing evidence of tumour recurrence on CT scan. A total of eight of the 36 patients (23%) developed post-RT gonadal deficiency by the end of follow-up at 8 +/- 3.1 years (+/- SD, range 3-11), but six were aged over 40 years at that time. GH deficiency was frequent, occurring in 94% of patients, usually from 2 to 3 years post-RT, while TSH deficiency and reduced ACTH reserve was uncommon (each 14%), and occurred later. In the subgroup of 12 patients with macroprolactinomas, results were broadly comparable. CONCLUSIONS Megavoltage RT produces a progressive fall in serum prolactin in the great majority of patients with prolactinomas, with a relatively low incidence of TSH or ACTH deficiency. As it is now clear that dopamine agonist therapy alone provides sufficient management for microprolactinomas, RT may be used for the long-term control of macroprolactinomas, together with interim dopamine agonist therapy. It allows pregnancy to be safely undertaken but, in view of the delayed onset of gonadal deficiency, its administration should be timed with respect to the desired onset of conception in women.  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