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   1601329篇
  免费   133743篇
  国内免费   2587篇
耳鼻咽喉   21671篇
儿科学   52926篇
妇产科学   46251篇
基础医学   228002篇
口腔科学   47258篇
临床医学   140960篇
内科学   315185篇
皮肤病学   34309篇
神经病学   130221篇
特种医学   64837篇
外国民族医学   474篇
外科学   244223篇
综合类   39704篇
现状与发展   3篇
一般理论   544篇
预防医学   122755篇
眼科学   36423篇
药学   121503篇
  2篇
中国医学   2991篇
肿瘤学   87417篇
  2018年   14836篇
  2016年   12968篇
  2015年   15089篇
  2014年   20734篇
  2013年   31442篇
  2012年   42723篇
  2011年   44909篇
  2010年   26438篇
  2009年   25388篇
  2008年   43154篇
  2007年   45396篇
  2006年   46181篇
  2005年   44797篇
  2004年   44217篇
  2003年   42285篇
  2002年   41413篇
  2001年   75796篇
  2000年   78450篇
  1999年   66476篇
  1998年   17757篇
  1997年   16365篇
  1996年   16336篇
  1995年   16037篇
  1994年   15089篇
  1993年   14234篇
  1992年   55512篇
  1991年   53839篇
  1990年   52611篇
  1989年   50898篇
  1988年   47287篇
  1987年   46595篇
  1986年   44340篇
  1985年   42894篇
  1984年   32071篇
  1983年   27596篇
  1982年   16160篇
  1981年   14449篇
  1980年   13578篇
  1979年   30493篇
  1978年   21075篇
  1977年   17775篇
  1976年   16703篇
  1975年   17597篇
  1974年   21507篇
  1973年   20695篇
  1972年   18868篇
  1971年   17780篇
  1970年   16299篇
  1969年   15267篇
  1968年   13949篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Cough and paradoxical vocal fold motion   总被引:8,自引:0,他引:8  
OBJECTIVES: The differential diagnosis and treatment of patients with chronic cough, paradoxical vocal fold motion, and disordered breathing can be a challenge to most practicing otolaryngologists. Tracheobronchial (ie, asthma, bronchitis, and tracheal stenosis), laryngeal (ie, vocal fold paralysis and neoplasms), and rhinologic (ie, allergies and rhinosinusitis) etiologies are commonly diagnosed and treated effectively. However, occasionally one is faced with patients who are refractory to medical treatment and have no obvious rhinologic, laryngeal or pulmonary cause. STUDY DESIGN AND SETTING: We conducted a review of the literature. METHODS: We present a thorough review of the current medical literature exploring the complex neurologic mechanisms involved in the production of cough and the relationship between gastroesophageal reflux disease, vagal neurapathy, and paradoxical vocal fold motion. RESULTS: The diagnosis and successful treatment of chronic cough can be complex. It requires a thorough understanding of the neurologic mechanisms behind cough excitation and suppression. Successful treatment strategies include aggressive management of the patient's reactive airway disease, gastroesophageal reflux disease, and, in select cases, paradoxical vocal fold motion. This may involve a well-coordinated effort among pulmonologists, otolaryngologists, gastroenterologists, and speech pathologists. CONCLUSION: Gastroesophageal reflux disease, vagal neuropathy, and paradoxical vocal fold motion are additional causes of chronic cough and disordered breathing that need to be considered, in the absence of obvious laryngotracheal and/or rhinologic pathology. A high index of suspicion is essential in making the diagnosis and formulating an effective multidisciplinary treatment plan for these patients.  相似文献   
992.
993.
994.
Tc-99m HMPAO was used to evaluate cerebral perfusion in a patient with tuberous sclerosis. The SPECT images demonstrated reduced HMPAO uptake in regions corresponding with MRI-confirmed locations of cortical tubers. These results indicate that the lesions are characterized by vascular perfusion deficits and support the hypothesis that cortical tubers result from developmental abnormalities of the embryonic central nervous system.  相似文献   
995.
Fifty to 100 children receive transplanted kidneys, hearts, livers, or bone marrow in Florida each year and many more bone allografts or other tissues (skin, cornea). Children are in the minority of the total solid organ transplantation but those with successful transplants are strong proponents of the procedure. Many (liver or heart failure) would have died without transplantation; others (kidney failure) would have lived but been tied to dialysis for life. The success rate varies with the organ or tissue transplanted. Some children return to a completely normal life without the need for immunosuppressive medications. Others require them continually. Cyclosporine, azathioprine and prednisone are the most frequently used. Rejection continues to be the leading cause of graft loss. Major impediments to solid organ transplantation are the paucity of acceptable organs and the high cost associated with maintenance of transplant patients.  相似文献   
996.
997.
1. The frequent occurrence of hypothalamo-pituitary dysfunction in patients with eating disorders as well as prior reports that nutritional and endocrine status influence pituitary morphology, led us to hypothesize that pituitary size and shape may be altered in patients with eating disorders. 2. Magnetic resonance imaging (MRI) does not use ionizing radiation and is currently one of the most feasible modalities available to study the pituitary gland in vivo. Using MRI, we have previously reported in a preliminary study that female patients with eating disorders had significantly smaller pituitary glands than controls. In addition MRI excluded any pituitary mass lesions. 3. In this report, we confirm our previous MRI findings and provide further evidence of pituitary abnormalities in an expanded sample of eating disorder patients. Preliminary data on pituitary volume estimates from MRI scans are provided for a subset of patients and controls.  相似文献   
998.
1. Rhesus monkeys were equipped with a novel intracerebroventricular (i.c.v.) cannula system and trained to respond under operant schedules of food presentation or termination of stimuli associated with the delivery of shock (escape). 2. CRH decreased food-maintained behavior in a dose-related manner over the range of (0.3-10 micrograms/kg) but did not affect escape responding, demonstrating a selective effect on food-maintained responding. 3. This selective effect was related to the tendency for responding to stop after delivery of a food pellet when higher doses of CRH were given, consistent with the notion that a conditioned aversion to food was established in the presence of CRH. 4. This may suggest that in hyperaroused clinical states such as depression and anorexia nervosa, focus is shifted away from appetitive tasks as a result of increased levels of CRH.  相似文献   
999.
Summary The prevalence of smoking, hypertension and diabetes mellitus was assessed in 221 patients suffering from internal carotid stenosis and compared with the prevalences in two sex- and age-matched control groups composed of subjects having normal Doppler findings and from non-neurological outpatients. Of the subjects with carotid stenosis 27.6% were hypertensive smokers in comparison with 9.5% and 17.2% in the two control groups. The difference of the stenosis cohort from the two control groups was significant (P<0.01 and P=0.016 respectively). There was no statistically significant differences between the occurrence of diabetes and hypertension in non-smokers and patients who smoked. In 394 investigated patients suffering from carotid stenosis or occlusion an obstruction index, based on the Doppler shift frequency, was calculated. This index was lowest in the normotentive non-smokers. It was only insignificantly higher in the hypertensive non-smokers but significantly so in the normotensive smokers. The index was highest in the hypertensive non-smokers. It was concluded that cigarette smoking, especially if associated with hypertension, is a determinant risk factor for carotid stenosis and occlusion.  相似文献   
1000.
The renin-angiotensin system has traditionally been associated with the regulation of fluid and electrolyte balance. In this review we summarize the data which ascribes a completely new function to this system, i.e., the regulation of alcohol consumption. In addition, we suggest a possible mechanism for this effect based on the concept of a satiety or stop process. The approach taken was to examine the effect on alcohol intake of a wide variety of drug, genetic, dietary, surgical and neurosurgical manipulations, each of which has a range of biological effects characteristic of that manipulation, but all of which share the common property of altering activity in the renin-angiotensin system. The effect of these manipulations on alcohol intake was most parsimoniously explained by reference to their ability to raise or lower activity in the renin-angiotensin system. Any intervention which modulates activity in this system, either directly or indirectly, is likely to have consequences for alcohol consumption.  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