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   1830678篇
  免费   146359篇
  国内免费   2899篇
耳鼻咽喉   25160篇
儿科学   61222篇
妇产科学   52957篇
基础医学   263289篇
口腔科学   53195篇
临床医学   160450篇
内科学   356716篇
皮肤病学   39330篇
神经病学   146369篇
特种医学   73756篇
外国民族医学   516篇
外科学   280114篇
综合类   45911篇
现状与发展   4篇
一般理论   692篇
预防医学   138886篇
眼科学   42111篇
药学   137823篇
  2篇
中国医学   3593篇
肿瘤学   97840篇
  2018年   17596篇
  2016年   15331篇
  2015年   17759篇
  2014年   24233篇
  2013年   37142篇
  2012年   49677篇
  2011年   52263篇
  2010年   31313篇
  2009年   29646篇
  2008年   49855篇
  2007年   52825篇
  2006年   53483篇
  2005年   51842篇
  2004年   51074篇
  2003年   48737篇
  2002年   47505篇
  2001年   85514篇
  2000年   88389篇
  1999年   74847篇
  1998年   20139篇
  1997年   18465篇
  1996年   18327篇
  1995年   17952篇
  1994年   16866篇
  1993年   15913篇
  1992年   61619篇
  1991年   60197篇
  1990年   58879篇
  1989年   57085篇
  1988年   52871篇
  1987年   52046篇
  1986年   49503篇
  1985年   47920篇
  1984年   35747篇
  1983年   30758篇
  1982年   18075篇
  1981年   16038篇
  1980年   15131篇
  1979年   33863篇
  1978年   23530篇
  1977年   19944篇
  1976年   18627篇
  1975年   19860篇
  1974年   24138篇
  1973年   23389篇
  1972年   21397篇
  1971年   20161篇
  1970年   18592篇
  1969年   17377篇
  1968年   15956篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Anorectal function in the solitary rectal ulcer syndrome   总被引:8,自引:6,他引:2  
The anorectal function of nine patients with solitary rectal ulcer syndrome (SRUS) (5 F: 4 M, median age, 27 (range, 19–41 years) and nine control subjects (5 F: 4 M, median age, 47 (35–66)P<0.01) has been investigated by a new technique that radiologically visualizes the anorectum during voiding of a semisolid contrast medium, while simultaneously measuring intrarectal pressure and anal sphincter EMG activity. A degree of rectal prolapse was demonstrated in eight of the SRUS patients; six of these lesions were clinically occult. Abnormal failure of the anal sphincter to relax on voiding was present in seven of the SRUS patients. These abnormalities resulted in the SRUS patients requiring a greater increase in intrarectal pressure (median, 100 cm water) to void than the control subjects (median, 65 cm water,P<0.01). This combination of high intrarectal pressure and rectal prolapse during straining seems to be the cause of SRUS This work was supported by a grant from the Medical Research Council.  相似文献   
992.
993.
994.
995.
The authors report the association of erythroleukemia (FAB M6) and fetal hemoglobin (HbF) level of at least 65% after therapy for ovarian carcinoma. The patient's erythrocytes had many signs of reversion to fetal-like erythropoiesis including: elevated HbF with a fetal G gamma/A gamma (gly/ala) of 3/1, low hemoglobin A2 (HbA2), macrocytosis, and increased i antigen. These data and data from other case reports suggest that elevation of HbF to greater than 25% with reversion to fetal-like erythropoiesis is useful in differentiating erythroleukemia from other preleukemic disorders.  相似文献   
996.
Ranitidine influences the uptake of oral midazolam.   总被引:1,自引:0,他引:1       下载免费PDF全文
In a randomised crossover study in volunteers plasma midazolam levels were estimated for 24 h following 15 mg by mouth, either preceded by no medication or following 24 h therapy with ranitidine. Administration of the H2-receptor blocker significantly increased bioavailability of the benzodiazepine and resulted in higher plasma levels for the first 6 h after taking midazolam. This was accompanied by a greater soporific effect.  相似文献   
997.
Neurogenic bladder dysfunction, characterized by hesitancy, need to strain, decreased stream, and increased duration of urination, developed in 104 (63%) of 166 employees working in the manufacture of polyurethane foam. Highest rates of illness (69%) occurred in production workers, and no illness occurred in office or warehouse workers. Onset of the epidemic coincided with introduction of a catalyst, dimethylaminopropionitrile (DMAPN), and monthly case incidence rates increased as DMAPN use increased. Outbreak ceased abruptly when DMAPN use was stopped. Of eight patients who underwent neurourologic testing during recovery, seven lacked either detrusor reflex or normal sensation of bladder filling; seven had a subclinical sensory abnormality; three had prolonged sacral-evoked responses; and two of these three had limb motor neuropathies. Dimethylaminopropionitrile is unique among known neurotoxins in producing urinary symptoms more frequently than limb nerve symptoms.  相似文献   
998.
999.
Seventy seven antral biopsies were collected from patients attending endoscopy clinic at King Khalid University Hospital, Riyadh, Saudi Arabia during a period of six months between December 1988 to May 1989. Of these 69 (89.6%) showed chronic gastritis as well as Helicobacter-like organisms (HLOs) in the biopsy specimens while 63 (81.8%) of biopsies grew Helicobacter pylori on culture. These findings indicate a good correlation between the histological diagnosis of chronic gastritis and isolation of H. pylori on culture.  相似文献   
1000.
Electrical activity was recorded from single cells in the thalamus of 10 patients with chronic pain associated with deafferentation. Under local anesthesia, these patients underwent either electrode implantation or thalamotomy for treatment of their pain. In eight of the 10 patients, single units were identified as discharging spontaneously in high-frequency, often rhythmic, bursts. The discharges were of two types: short bursts comprised of two to six spikes with a burst frequency of one to four per second; and long trains of 30 to 80 spikes of similar frequency. Reconstruction of electrode trajectories indicated that recordings were made from the region corresponding to the lateral aspect of the mediodorsal thalamic nucleus, the central lateral nucleus, a small part of the central median nucleus, and the parafascicular nucleus. In the eight patients in whom spontaneous neuronal burst activity was exhibited, it was impossible to study activity evoked by natural cutaneous stimulation due to the continuous spontaneous neuronal discharges. Both animal and human studies have suggested that pain related to deafferentation is accompanied by spontaneous hyperactivity in the dorsal horn of the spinal cord and in the ventral posterior thalamic nuclei. The authors present evidence of spontaneous neuronal hyperactivity in the intralaminar thalamic nuclei of patients with pain related to deafferentation. The findings suggest that spontaneous neuronal discharge in patients with pain related to deafferentation is more widespread in the central nervous system than has been previously appreciated. The results have important implications for the surgical treatment of chronic pain.  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