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   2374611篇
  免费   195039篇
  国内免费   4209篇
耳鼻咽喉   34264篇
儿科学   72747篇
妇产科学   62928篇
基础医学   334869篇
口腔科学   67522篇
临床医学   215512篇
内科学   468572篇
皮肤病学   47930篇
神经病学   200771篇
特种医学   95956篇
外国民族医学   886篇
外科学   360384篇
综合类   56218篇
现状与发展   1篇
一般理论   977篇
预防医学   190598篇
眼科学   55462篇
药学   177519篇
  4篇
中国医学   4367篇
肿瘤学   126372篇
  2018年   24203篇
  2016年   20576篇
  2015年   23281篇
  2014年   33532篇
  2013年   50828篇
  2012年   68739篇
  2011年   72275篇
  2010年   42470篇
  2009年   40860篇
  2008年   68757篇
  2007年   73093篇
  2006年   73993篇
  2005年   72032篇
  2004年   69331篇
  2003年   67010篇
  2002年   66257篇
  2001年   112449篇
  2000年   116525篇
  1999年   98333篇
  1998年   27858篇
  1997年   25522篇
  1996年   25447篇
  1995年   24609篇
  1994年   23159篇
  1993年   21552篇
  1992年   79386篇
  1991年   76393篇
  1990年   73575篇
  1989年   70841篇
  1988年   65846篇
  1987年   64800篇
  1986年   61334篇
  1985年   58399篇
  1984年   44222篇
  1983年   37657篇
  1982年   22886篇
  1981年   20333篇
  1980年   19034篇
  1979年   41299篇
  1978年   28985篇
  1977年   24346篇
  1976年   22832篇
  1975年   23964篇
  1974年   29638篇
  1973年   28042篇
  1972年   26226篇
  1971年   24151篇
  1970年   22752篇
  1969年   21087篇
  1968年   19135篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
We report histological changes in four patients with port wine stains treated with 578 nm yellow light from a high power copper vapour laser. Histology showed that selective damage occurred to the ectatic blood-vessels in the dermis, without haemorrhage and damage to non-vascular structures, and without scarring. The initial damage to the overlying epidermis was not permanent, and the damaged ectatic vessels returned to normal size or were completely necrosed and replaced by collagen.  相似文献   
942.
The gold standard for therapeutic trials is the randomized, double-blind, placebo-controlled study design. Lack of blindness and placebo makes tenuous the attribution of results to the specific agent; lack of randomization between concurrent and comparable groups makes it impossible. The chi-square test of the null hypothesis of no difference between treatment groups is the best method of assessment, as no overall rating system used in neurology is a true numerical scale but at best a rank-order scale. If quantitation of results is desired, a nonparametric rank-order test is necessary. Results over time can be assessed with a logrank (life-table) test for single events as end point, and by chi-square or rank-order tests for multiple events among individual patients.  相似文献   
943.
944.
We tested whether hypoglycemia, like hypoxia, would preferentially destroy GABAergic nerve cells in the neocortex. To this end, rat neocortex explants dissected from 6-day-old rat pups and cultured up to a developmental stage approximately comparable to that of the newborn human neocortex, were exposed to hypoglycemia for different periods. Quantitative light microscopic and immunocytochemical evaluation of the cultures demonstrated that hypoglycemia does not preferentially destroy GABAergic but rather non-GABAergic neurons, a finding quite opposite to what was found after hypoxia. Recent biochemical data from other laboratories which seem to support this difference in neuronal vulnerability are discussed. It is concluded that perinatal hypoglycemia may not form such a serious threat with respect to the genesis of epilepsy as does hypoxia.  相似文献   
945.
A peculiarly effective intervention by the author's psychoanalyst is explored and discussed in terms of its implicitly expressive properties. It is placed in the context of the classical concept of opacity and more flexible Sullivanian ideas, as expanded and clarified by Havens.  相似文献   
946.
The results of this controlled study of the treatment of 57 patients with Gilles de la Tourette's syndrome suggested that both haloperidol and pimozide were more effective than placebo, but that haloperidol was slightly more effective than pimozide. Adverse effects occurred more frequently with haloperidol vs placebo than with pimozide vs placebo, but the frequency was not significantly different for haloperidol compared with pimozide. Clinically significant cardiac effects did not occur at a maximum dosage of 0.3 mg/kg or 20 mg/d for pimozide and 10 mg/d for haloperidol. However, the QTc interval was prolonged during pimozide treatment compared with that during haloperidol treatment, although the values for both medications were not in an abnormal range.  相似文献   
947.
To assess the relationship between the DSM-III criteria for attention deficit disorder with hyperactivity (ADDH) and the DSM-III-R criteria for attention-deficit hyperactivity disorder (ADHD), children from an inner city parochial school were evaluated using a 30-item teacher questionnaire consisting of the DMS-III and DSM-III-R criteria for these disorders, the revised Conners Parent and Teacher Questionnaires, and a continuous performance test. Diagnostic groups were established based on teacher ratings of the DSM items and evaluated in relation to the rating scale data and continuous performance test. While children who were identified by teachers as having ADDH almost always satisfied the criteria for ADHD, a new group of children who were hyperactive and impulsive but less clearly inattentive also met the criteria for ADHD. Implications of the change in diagnostic criteria are discussed.  相似文献   
948.
949.
950.
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