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   1310655篇
  免费   82704篇
  国内免费   2009篇
耳鼻咽喉   16360篇
儿科学   36150篇
妇产科学   30556篇
基础医学   177874篇
口腔科学   34033篇
临床医学   111725篇
内科学   256886篇
皮肤病学   22533篇
神经病学   107864篇
特种医学   52427篇
外国民族医学   92篇
外科学   213836篇
综合类   23883篇
现状与发展   3篇
一般理论   515篇
预防医学   97811篇
眼科学   28060篇
药学   95953篇
  4篇
中国医学   3117篇
肿瘤学   85686篇
  2021年   8658篇
  2019年   9012篇
  2018年   35039篇
  2017年   27868篇
  2016年   31917篇
  2015年   13498篇
  2014年   18298篇
  2013年   26291篇
  2012年   42791篇
  2011年   59384篇
  2010年   40925篇
  2009年   32940篇
  2008年   57748篇
  2007年   62957篇
  2006年   39662篇
  2005年   41327篇
  2004年   41463篇
  2003年   41370篇
  2002年   38296篇
  2001年   56876篇
  2000年   58580篇
  1999年   49073篇
  1998年   13602篇
  1997年   12044篇
  1996年   11817篇
  1995年   10921篇
  1994年   10098篇
  1993年   9278篇
  1992年   36744篇
  1991年   35129篇
  1990年   33867篇
  1989年   32867篇
  1988年   30037篇
  1987年   29314篇
  1986年   27323篇
  1985年   26228篇
  1984年   19276篇
  1983年   16566篇
  1982年   9579篇
  1981年   8298篇
  1979年   16628篇
  1978年   11554篇
  1977年   9939篇
  1976年   8737篇
  1975年   9259篇
  1974年   11130篇
  1973年   10413篇
  1972年   9755篇
  1971年   9173篇
  1970年   8754篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
991.
Relapsing polychondritis is an autoimmune disease that affects all body cartilages. The disease may also involve the audio-vestibular system, usually bilaterally. Most of the reported cases were adults 20 years old or more. This is a case report of a 12-year-old girl with unilateral sensorineural hearing loss, and a review of the literature.  相似文献   
992.
Ethmoidal mucocoeles in children   总被引:1,自引:0,他引:1  
Children presenting with ethmoidal mucocoeles are rare. Five children are presented with such findings, and the diagnosis, treatment and possible aetiology discussed. C.T. scanning was found to be the investigation of choice, while plain sinus X-rays correlated poorly with the presence of disease. Exenteration through an external approach was found to be satisfactory. In two cases drainage obstruction due to congenital abnormality was thought to be the underlying cause, while in four cases there was a strong history of atopy, indicating allergy as a possible reason for mucocoele formation.  相似文献   
993.
Unintelligible speech in childhood is often characterised by the use of unusual or deviant (i.e. non-developmental) phonological processes, e.g. initial consonant deletion. These processes are reported to appear at speech onset and to undergo little spontaneous change during the preschool years. The study reported here documents the changes that occurred in the phonological systems of seven phonologically disordered children during remediation that targeted unusual phonological processes. Qualitative changes in phonological process use were observed for all children. Six of the children made quantitative improvement in terms of the percentage consonants produced correctly in spontaneous speech. Individual differences in phonological learning strategy use are described.  相似文献   
994.
This paper reports the results of an experimental study modeled after a study conducted by Kaplan et al. The hypothesis tested was: Adolescents who receive a social learning intervention (SLI) will show greater improvement in metabolic control of their diabetes than will adolescents who receive only traditional diabetes instruction. Thirty-four adolescents between the ages of 12 and 16 who attended a midwestern camp were randomly divided into two groups. Both groups attended a daily 1-hour teaching session about diabetes. Later each day, the experimental group received an SLI consisting of role modeling to help the subjects circumvent peer pressure. To determine metabolic control, HbA1 values were determined before and 3 1/2 months after the intervention. The control group showed no significant difference in HbA1 values, while the experimental group showed a decrease in metabolic control.  相似文献   
995.
The authors studied the clinical features and outcome at 6 months in 191 patients with subarachnoid hemorrhage (SAH) from ruptured aneurysms. Aneurysm repair (AR) was undertaken in 123 cases (64.4%). In the non-AR group (n = 68), 48.5% of the patients were 70 years of age or older, compared with 12.2% in the AR group. The duration from onset to admission was less than 3 hours in 48 non-AR cases (70.6%) and in 42 AR cases (34.1%). Among non-AR patients, 63.2% were Hunt and Hess grade IV or V, whereas the figure for AR patients was only 14.7%. By 6 months after SAH, 94.1% of non-AR patients had died, and the remainder were vegetative or severely disabled. In contrast, only 15.4% in the AR group died, and over 50% showed good recovery. The large majority of non-AR patients were treated conservatively because they were judged to be poor surgical risks and, among these patients, nearly one half were elderly. In the 10 elderly patients considered good surgical candidates, vasospasm was the most common reason (70%) for not performing AR.  相似文献   
996.
Patients with bulimia (binge-purge syndrome) frequently complain that they consume a very restrictive diet to avoid gaining weight. To investigate this claim, 23 hospitalized bulimic patients were assessed daily for body weight, caloric intake, macronutrient diet content, activity measures, and body composition estimates during weight-stable periods. Bulimic patients ate fewer kilocalories per kilogram body weight (22.1 +/- 4.6 kcal/kg) than did age-matched normal women (29.7 +/- 6.5 kcal/kg) but had similar activity levels and body composition. Clinical variables, such as history of laxative abuse, anorexia, or obesity, and physiological characteristics, such as body weight, activity level, or dietary content, could not account for this difference in caloric consumption. Bulimic patients tended to eat a diet lower in fat and higher in protein than did control subjects. These results agree with observations of increased efficiency of caloric utilization in obese patients and support patient complaints of a tendency to gain weight easily.  相似文献   
997.
998.
The estimation of breakthrough time for multicomponent organic solvent vapors on activated carbon fixed beds is significantly complicated and difficult. This paper describes a simple estimation method of breakthrough time for the first component (foremost breakthrough component) in two- or three-component organic solvent vapors on an activated carbon fixed bed. The breakthrough time for the first component was expressed by the harmonic mean value of the breakthrough times in each pure component. Estimated breakthrough times were compared with the experimental ones.  相似文献   
999.
Catecholamine (CA) release was measured in vivo in the monkey and cat visual cortices electrochemically. Stereate-modified, graphite-paste electrodes were used to monitor changes in norepinephrine and dopamine release. Micromolar changes in CA concentration were obtained by stimulation of the eye with nonspecific (strobe) or specific (oriented bars, radial gratings) stimuli. CA release depended on which eye was illuminated. Electrodes passed tangentially through the striate area recorded release following visual stimulation of one eye or the other in succession, and the shift in eye dominance occurred at about 500 microns intervals. The magnitude of CA release was highly correlated with the ocular dominance of neuronal activity measured with tungsten microelectrodes. Light-stimulated release was not recorded in monkey area V2, V4, or somatosensory area 1, but was recorded in cat V2, suggesting that the presence of LGN afferents is associated with CA release. Results are discussed in terms of the role of geniculate activity and the specific role of CAs in cortical information processing.  相似文献   
1000.
The dorsal column nuclei and the sensory trigeminal nuclei project not only to the ventrobasal thalamus but also to the cerebellum. In this study the numbers and distribution of neurones projecting to these two regions were examined for the following nuclei: the rostral part of the main cuneate nucleus, the external cuneate nucleus, nucleus x, the principal sensory nucleus of the trigeminal nerve, and the oral, interpolar, and caudal subnuclei of the spinal nucleus of the trigeminal nerve. A thalamic projection from nucleus x and from the external cuneate nucleus was confirmed, and a distinct group of neurones projecting to the ventroposteromedial thalamus was distinguished near the ventromedial aspect of the principal sensory nucleus. Of the 165,000 neurones examined, only one was found to be double labelled. It was concluded that the populations of neurones that project to the ventrobasal thalamus and to the cerebellum are separate, and that somatosensory neurones in the brainstem do not send axon collaterals to both regions.  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