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   7766篇
  免费   437篇
  国内免费   37篇
耳鼻咽喉   79篇
儿科学   196篇
妇产科学   376篇
基础医学   969篇
口腔科学   178篇
临床医学   544篇
内科学   1987篇
皮肤病学   212篇
神经病学   731篇
特种医学   266篇
外科学   1113篇
综合类   30篇
一般理论   1篇
预防医学   296篇
眼科学   45篇
药学   607篇
中国医学   15篇
肿瘤学   595篇
  2023年   35篇
  2022年   69篇
  2021年   114篇
  2020年   91篇
  2019年   143篇
  2018年   156篇
  2017年   115篇
  2016年   143篇
  2015年   136篇
  2014年   195篇
  2013年   264篇
  2012年   446篇
  2011年   385篇
  2010年   228篇
  2009年   232篇
  2008年   411篇
  2007年   410篇
  2006年   404篇
  2005年   354篇
  2004年   405篇
  2003年   330篇
  2002年   312篇
  2001年   224篇
  2000年   273篇
  1999年   230篇
  1998年   85篇
  1997年   63篇
  1996年   95篇
  1995年   74篇
  1994年   52篇
  1993年   61篇
  1992年   166篇
  1991年   173篇
  1990年   152篇
  1989年   141篇
  1988年   125篇
  1987年   98篇
  1986年   94篇
  1985年   87篇
  1984年   70篇
  1983年   70篇
  1982年   39篇
  1981年   39篇
  1979年   44篇
  1978年   30篇
  1977年   28篇
  1976年   28篇
  1975年   43篇
  1974年   32篇
  1973年   29篇
排序方式: 共有8240条查询结果,搜索用时 18 毫秒
21.
Circulating prolactin (PRL) levels, dopamine (DA) content, in vitro basal and stimulus-evoked endogenous DA release from arcuate-periventricular nuclei median-eminence fragments were studied in young (4 months) and old (24-25 months) male rats of Sprague-Dawley strain. Serum PRL levels did not differ in young and aged animals. In addition DA tissue content, basal and K+- or d-amphetamine evoked endogenous DA release did not show age-related differences. These results suggest that in male rats of the Sprague-Dawley strain the activity of tuberoinfundibular dopaminergic (TIDA) neurons does not change during senescence, unlike what happens in other strains of rats.  相似文献   
22.
23.
24.
25.
No direct measurements of the pressures produced by the ribcage muscles, the diaphragm and the abdominal muscles during hyperventilation have been reported in patients with ankylosing spondylitis. Based on recent evidence indicating that abdominal muscles are important contributors to stimulation of ventilation, it was hypothesised that, in ankylosing spondylitis patients with limited ribcage expansion, a respiratory centre strategy to help the diaphragm function may involve coordinated action of this muscle with abdominal muscles. In order to validate this hypothesis, the chest wall response to a hypercapnic/hyperoxic rebreathing test was assessed in six ankylosing spondylitis patients and seven controls by combined analysis of: 1) chest wall kinematics, using optoelectronic plethysmography, this system is accurate in partitioning chest wall expansion into the contributions of the ribcage and the abdomen; and 2) respiratory muscle pressures, oesophageal, gastric and transdiaphragmatic (Pdi); the pressure/volume relaxation characteristics of both the ribcage and the abdomen allowed assessment of the peak pressure of both inspiratory and expiratory ribcage muscles, and of the abdominal muscles. During rebreathing, chest wall expansion increased to a similar extent in patients to that in controls; however, the abdominal component increased more and the ribcage component less in patients. Peak inspiratory ribcage, but not abdominal, muscle pressure was significantly lower in patients than in controls. End-inspiratory Pdi increased similarly in both groups, whereas inspiratory swings in Pdi increased significantly only in patients. No pressure or volume signals correlated with disease severity. The diaphragm and abdominal muscles help to expand the chest wall in ankylosing spondylitis patients, regardless of the severity of their disease. This finding supports the starting hypothesis that a coordinated response of respiratory muscle activity optimises the efficiency of the thoracoabdominal compartment in conditions of limited ribcage expansion.  相似文献   
26.
Patients with Taylor-type focal cortical dysplasia (TTFCD) generally present with medically intractable epilepsy and impaired neurological and/or intellectual functioning. Surgery usually proves to be the only treatment approach leading to control of seizures. We describe a 17-year-old girl with TTFCD who exhibited a very long period of seizure remission. Combined clinical and neuroimaging findings were compatible with a diagnosis of a balloon cell-subtype TTFCD. As for the clinical course, partial motor seizures began at one year of age and ceased at five: our patient has had no seizure recurrence over a 12-year-follow-up. Moreover, throughout the 15-year follow-up, neurological examinations and cognitive abilities always remained within normal limits. Neuropsychological assessment clearly showed no impairments in executive functions: planning abilities, working memory, attention and impulse control, or constructive aspects of motor coordination. The predominant deficits pertained to verbal abilities in the context of borderline intellectual performances. To our knowledge, this case report documents the longest duration of seizure remission in a patient with TTFCD, thus emphasizing the possible benign course of such dysplastic lesions which usually have a poor prognosis, leading to early surgical treatment.  相似文献   
27.
Repetitive conservative surgery for recurrence of endometriosis   总被引:4,自引:0,他引:4  
We evaluated the recovery of fertility and the relief of pain symptoms in a long-term follow-up of 42 women undergoing repetitive conservative surgery for recurrent endometriosis. The mean age of the patients was 31.1 +/- 4.3 years. At the time of their second operation the disease was stage IV in 14 women, stage III in 25, and stage I in three. After reoperation, the patients were followed for a mean period of 41.8 +/- 30.3 months. Pain symptoms returned in eight women, dysmenorrhea and deep dyspareunia in eight, and pelvic pain in seven. Eight of the 28 women (28.6%) who attempted to conceive achieved a total of 13 pregnancies. The corrected pregnancy rate was 35%, and the cumulative rate at 27 months was 30.7%. A third operation was necessary in six women after a mean period of 35 months. Conservative surgery is an effective therapeutic option for infertile patients with recurrent endometriosis.  相似文献   
28.
The protection by pyroglutamic acid (CAS 98-79-3) and derivatives Ia-i (injected i.p.) against glutamate- and NMDA (N-methyl-D-aspartate) (i.c.v.) induced seizures in mice has been studied in comparison with known antiepileptics and antagonists of excitatory aminoacids. The potency of pyroglutamic acid and some derivatives (Id,f,g,h) against glutamate-induced convulsions was similar to that shown by glutamic acid diethylester and by valproic acid. Interestingly, pyroglutamic acid did not affect NMDA-induced convulsions which were well antagonized by both 2-amino-5-phosphono valeric acid and by diazepam. Thus, pyroglutamic acid may represent the starting for synthesis of excitatory aminoacid antagonists acting at non NMDA receptors.  相似文献   
29.
30.
We determined morphine plasma concentrations in 6 cancer patients before and with administration of diclofenac for 5 days. The non-steroidal anti-inflammatory drug does not modify morphine bioavailability. This observation suggests that diclofenac can be used in association with morphine during cancer pain treatment, without increasing the risk of overdosage or side effects of the opiate.  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